Low Cost Great Pen, Bundled with Not-So-Great Ink.
355521
Do not buy these for the ink in the cartridges which come with them -- it's not very good ink, the colors aren't strong and they aren't bright.  But the pen -- it's a great pen, and at the price they cost, if you lose one, you aren't out hundreds of dollars -- which is what I think this pen writes like.  I'd compare this under-$4 pen favorably to pens costing 20 times as much.  Of course, to properly use this pen, you will require the Platinum fountain pen converter, which costs more than the pen, bringing the total for the pen and converter to about $10.  Or you can empty the old ink from a cartridge and refill with your favorite.  This pen will handle nearly any fountain pen ink you put into it, and it writes evenly and without skipping.  The inks I've tried in these pens are the Herbin Rose ink, Herbin green, Private Reserve Sherwood Green, Private Reserve DC Super Blue,  and Private Reserve Plum.  Others have tried Noodlers and say it works well too.  For this price, you can have a bunch of colorful fountain pens that let you write in whatever color suits your mood (provided, of course, you purchase tasteful inks).  The review is down one star because of the inks provided.
708839
The ink flows nice and smooth. The pen writes wonderfully. It looked like it was cheap and not worth it, but it was!
3840046
I received the pen (ordered from Amazon) from my boss' wife as a gift. It's a good pen although I don't feel anything special about the ink (like ball pt pens). The rubber grip makes it easy to write throughout long days and having 4 colors help keep yourself organized. Overall, for $5, I can dig it. *****
1515129
I'm a fanatic about the Uni Jetstreams. The ink, the grip, and the shape come together in a big way and make for a great experience.

That being said, and I see it has been mentioned by multiple other reviewers, it would seem that this pen has a slick feel and not so much of the grip that I like on the standard (US sold) Jetstreams. Not even really a 'gel' grip as indicated by the name Alpha-gel. Not that big of an issue, but combined with a slightly cheaper feel than the the standards, I can't in good faith give it a full 5-stars.

If you already like these pens, I don't think you can go wrong dropping $8 on a couple shipped from Japan.
3010547
Great writing pen, it glides smoothly on the paper, I like the cartridge and reservoir options but the reservoir doesn't hold as much ink as I would like- other than that it's a great pen.
2327456
I bought this because I wanted a fountain pen with flex nib for drawing away from my dip pens, and I was really surprised to find one at this price! It's mostly a good pen at a great price, which I like about Noodlers. The problem is, it has a tendency to accumulate a lot of ink on the face of the nib, which then can dirty the grip and the inside of the lid. It's a mess, and it makes it not worth carrying the pen around in my bag.
631984
This is not the greatest pen in the world. I love the design of it, and the price isn't that bad either, but it does have some serious writing issues. Out of the box, I could not get the pen to write, as the ink flow was practically nonexistent. I was able to remedy this by taking a small syringe and injecting some black ink from a dip-pen bottle into the mouth of the cartridge to loosen everything up. I like that this pen lays down a bold line, and I've been using it for a few days now, but I still believe that it shouldn't require modifications out of the box just to work. Another small negative is that this pen does not accept standard size ink refills, only the cartridges it came with. I'd definitely recommend considering an alternative if you're looking for a fountain pen.
4187670
I have the Uni Jetstream 4 & 1, but it is a tad bulky, so I thought I would give the Zebra a try. It is smaller in circumference than the Uni, and for me it is more comfortable to write with. The downside is the ink. It pales in comparison to the Uni Jetstream ink. It's pretty much what you can expect out of most cheap inks. That being said, the ink isn't bad enough to stop me from using the pen. It is comfortable to write with without having to carry multiple pens, and I like the hinged clip for easy placement into my shirt pocket. It's also nearly half the price of the Uni, so if you are looking for an affordable, quality multipen with pencil, the Zebra is a good choice.
4819744
Keep in mind, this is an incredibly cheap fountain pen. It writes very smoothly (I've been using it for months and have had no problems with ink flow consistency). It does start kind of dry when you first put in a new cartridge and you have to baby it a little to get it going, but once it starts flowing, it's good. The barrel and cap are made of very cheap plastic, so you have to be a little careful with it. The cap unscrews, so don't yank on it, or it will break. If you drop it,  it will spit a couple of drops of ink into the clear cap, and you'll have to rinse it. If you are looking for an entry-level fountain pen that writes well, with a price tag that won't hurt too much if it gets stolen or busted, this pen is a good place to start. I've owned pens that cost 3x as much that I've liked way less.
21148
Overall I'm having fun with this pen.  It has a good amount of flex to give your writing some character but it takes a little time to figure out how to use it to get the lineweight variation that it's capable of.

My main complaint is that it dries out really fast; I've used both quink and noodler's eternal blue and with both inks it will dry out overnight.  It also leaks ink heavily from the top side of the nib.

I have yet to try any of the heat treating methods, but that might be my next step.  For the price, this is a decent flex pen out of the box.
3545776
I received this pen yesterday, and it wrote poorly out of the box, with hard starts, skips, and just overall scratchiness. It also leaked ink, since the cartridge came out of its socket during shipping. After cleaning this pen, I first tried flushing the pen thoroughly and putting it in detergent. It still had hard starts, and I had to press down hard to get ink to come out smoothly without skipping. I looked this up online, and found that the pen's nib has an issue called "Baby's Bottom". This is apparently fairly common on Kaweco nibs. I used my loupe, and was able to clearly see this defect on the nib. You can find more information on this issue here: (Google 'Pen Addict Smooth as a Baby's Bottom')

After figuring out what the issue was, I used Goulet Pen's micro-mesh and mylar paper to smooth out the nib. After about 45 minutes of tuning, I was able to get this pen to write really well - better than my untuned Lamy Safari, which is a very smooth pen. Of course, it cannot compete with my Lamy 2000, but is still impressive at this price point. I plan to use this as a pocket-carry pen that I can take everywhere.

One other thing you should be aware of is that you are likely going to have to use cartridges for this pen, as there are no good converter options. Another option is to convert it into an eyedropper pen, which might appeal to some people. One tactic that I would recommend is to refill the cartridges using a syringe, as they are relatively easy to empty, flush, and refill. I was able to fill it with Sheaffer's Skrip Blue bottled ink and it worked perfectly.

Overall, I recommend this pen for someone looking for a thin and light pen to carry around with them. It's great for traveling, and once it's been tweaked, it writes very smoothly. If you are looking for the smoothest possible write, a pen that can use converters well, or have really large hands, this may not be the pen for you.
3125301
I also got a black one of these from a separate order, writes a bit smoother - All Jinhao in this model say 18k GP, meaning gold plated - this one is not gold plated, but has the same nib as others. I mean it is an inexpensive pen... meaning - when it comes to you it may not write the way you want and you will have to do some work - mine came and it was far to broad and wet of a writer, was a bit scratchy too. Aligned and flossed the tines, sanded the nib on ultra fine grit and its an decent writer. DISCLAIMER: What you do to your to your pen is on you, not me. I am obviously keeping this pen due to the work I put into it. I have other brands such as Montegrappa - no comparison, but for the money - it's an ok pen. I really like the black one better because the nib has the platting.
This pen does have a great shape, I post the cap when I write - it fits my hand perfect - very comfortable. Now that I have the nib the way I like it - I use this pen almost daily - it's a decent writer for a steal of a price. I do wish there was a bit more attention to the QC - my other one needed a bit of work but not near as much. It does come with a converter - which is nice, but I also have the Jinhao cartridges as a back up when I travel.
838655
Ever wonder why it was so easy to just throw in a "free pen" with a bottle of ink?  Now I know why.  The quality of the ink is magnificent.  A luxurious black that flows easily.  The eye dropper on the bottle is a tad flimsy and not securely set.  On first use, the squeeze bulb wobbled from the plastic housing and already globbed my finger with a bubble of ink.  No matter.  Fountain pens are messy right?  The enclosed pen is light, and very easy to write with.  However, on its second use, while pausing in mid-sentence, a glob of ink dripped right out of the nib on to my page - TWICE.  I undertstand that adjustments are often made or needed on pens, but the second day, its raining ink on my journal.  Great looking ink, but beware of the pen.  Had high hopes.  At least the ink is nice.
2616794
Pros (+) and Cons (-):
(+) They're 0.3mm.  That alone makes these a steal at $15.
(+) They come in an assortment of READABLE colors!  (I can't emphasize "readable" enough!)
(+) They're gel ink.  This means they flow nicely and water damage takes longer to wipe away your writing (ok, in terms of waterfast-ness, water-based < gel < oil < permanent, but who writes with permanent!? They're the smelliest, bleediest things pens out there.)
(-) Not so much the fault of the refills, but the 5-slot pen they go in isn't a 100% tight/locking (not as much as the Pilot G-2 pens), so you'll feel an ever so slight "brush" effect on certain strokes.  Like, there's a slight "give" depending on how you write, but this is very, very slight.  Some people won't even notice this.
(-) The pen these refills go in is 100% plastic, and isn't exactly weighted like high end ones.  This won't be a problem to most users.
(-) The instructions are all in Japanese (but a quick youtube and you'll be on your way.  It just caught me off guard that's all.)

Honestly, I'm only docking points for the lack of English instructions and that slight "give", other than that, these are hands down the "finest" pen refills you'll find (for a multipen).  Har har.
4968363
The ink tends to dry easily. This pen needs a upgraded ink cartridge. However, the pen looks great out the package.
1015122
Good fountains pens for the price.
These took a while to get to me (lost package) but I was happy when they arrived.

I've flushed and filled the converters in each of the pens.
6 of the 8 of these pens write smoothly. The orange and black demonstrators don't. Unfortunately those are the ones I was looking forward to the most. The nibs on those two are scratchy as of now. The ink flow on the orange one is mediocre unless pressure is applied while writing. I'm going to try smoothing out the nibs and separating the tines on the orange one.
The other 6 have smooth nibs with good ink flow.

These Jinhao pens have "medium" nibs. I've measured and compared lines. These nibs produce a little under 1mm lines, comparable to a 0.9 pencil.
Convertors seem a little fragile, but none have leaked so far.

I actually prefer these pens over Lamy Safaris. These Jinhaos are light and easy to hold. Lamys are heavier and too top heavy when caps are posted. For the price of 8 of these, you could only get one Lamy.

These pens would be good for students and everybody looking for a low cost pen.

Overall, Ive had a good experience with these pens. Will update as needed.
3481452
I love the feel of this pen; it's lightweight without feeling cheap and plastic-y and its tapered girth make it comfortable for extended writing.

I'm not crazy about the writing point, though. It's advertised to be a .7mm, but it writes more like a .5mm -- kind of a sharp and scratchy feeling on the paper, not smooth and fluid like my Fisher. But that's just a personal hangup of mine. Don't let that take away from the fact that this is a fantastic pen, and a bargain for what it is. The next closest pen to this on the market will cost twice what you'll pay for the Airpress.