Great features for the money.
930836
The YN560IV has worked well for me so far and is a great addition the the Yongnuo line up. In TX mode it fully controls power and zoom of the YN560iii and fires YN603's or YN605's. In RX mode it acts just like another YN560iii, and of course it can be used as a on camera flash or a simple optically triggered off camera flash. This is a manual flash with a single firing pin (no-TTL) and should work with any brand camera that has a standard hotshoe.

The controls are slightly more complex than the yn560iii but it's just like anything new with a minor learning curve. I find the YN560TX a little easier to use for changing settings on the remotes, but this product does make the 560TX unnecessary if you are on a tight budget. It fires fine in RX mode with the 560TX or 603 and has access to all 6 groups in both TX and RX modes. Range seems to be similar to others in this series (603, 560tx) and works fine in a mid sized reception hall (haven't tried it in a large hall). It is compatible with the newer yn605 which has group control, but I have not tested this. Output is as good as most other speedlights out there, although I did not test it precisely using a light meter. When in any slave mode (RX, S1, S2) an LED on the front flashes, I find this bit annoying in dark venues and cover it with a piece of black tape which significantly attenuates the brightness.

The battery compartment door seems pretty solid (this was an issue on some earlier Yongnuo speedlights). The 560iv has a port for an external battery pack that should fit Canon compatible packs. Like similar flashes, it has a pull out diffuser and bounce card. The PC port is a traditional threaded style. The head swivels (with detents, but no lock) to the right 90 degrees and to the left 180 degrees, it would be nice if it also swiveled to the right 180. Elevation is from about -5 degrees to 90. The shoe tightener is the screw down style Yongnuo has used for a long time, many people prefer the quick release flip type lock that Canon uses (doesn't matter too much to me). The flash does not have a USB port or obvious way to upgrade firmware. Size is similar to other full sized speedlights such as the 580ex-ii or SB900, and is exactly the same size as the YN560iii. The main display is back lit, but the buttons are not.

It comes packaged with a small stand like most other flashes in this price range or higher, as well as a decent quality pouch, and some instructions that while not great, are understandable.

This series (560iii, 560IV, 603, 605) is the best bang for the buck on the market right now (late 2014) for manual speedlights. The cost difference between the model iii and iv is minimal making the iii somewhat obsolete so if you are just putting together a new setup, I suggest going straight for the 560iv.  Of the competition I considered, the Godox V850 has the advantage of battery life over this (and pretty much every other speedlight out there), but it requires an external RX dongle that falls off easily, doesn't have a built in transmitter, has poor remote range, and more a limited remote feature set than the 560TX or the 560IV in TX mode.

For a minimal investment one can have a complete on camera/off camera manual system (sans modifiers) that works quite reliably. And if you want to incorporate some monolights into your setup, the YN605 is a great option which enables you to selectivity enable/disable certain groups from remote.

I will try to answer any questions left in the comments. Like this review if it was helpful to you.
3332969
Great quality for the money.  Smoothly operates. Very attractive and useful.
713460
Can't beat it for the money.  Most features of the much more expensive phones.  Camera OK, but what do you expect for the money?
4041646
Only had it up and running a few days now. I think 5 stars for the money for sure. So far so good. Looks great, I didn't have to adjust anything to my liking, it was to my liking out of the box. For 1k to 2k I could probably get a little better 30" monitor. But, for the money I'm very impressed and totally satisfied.
3207392
Pretty nice system for the money. The app via phone doesn't control as much as I'd like (you need to be at home on a PC to update preferences / turn on/off recording preferences for the system). Still really nice to be able to check in on what's going on around the house in real time when you're away.

I wish you could have multiple preferences to easily toggle between performance modes-- one for weekends vs weekdays vs vacation.

The night vision is surprisingly useful , you can see out into the yard a good ways even in the middle of the night. One of the cameras wasn't working in night mode and was quickly replaced. I might shop around a bit more and do more research on the user interface, but overall we like it.
3464478
A very nice timepiece for the money. Watch, alarm, countdown timer, second zone function...very functional. I've owned a few Casio watches, all of them worked just fine.
4830568
We bought this as a gift for my daughter, and it's been a great value for the money!  The controls are easy to learn and use...loading music is a snap...and the sound is really great!  Some may balk at the small screen and the plastic construction...but for the money it's an excellent value.  As for the screen...the player is smaller than a pack of tic-tacs, so it's actually pretty good.  For the record, while plastic, it is fairly solid (though lightweight) and the buttons are well made (not loose or jiggly).  Plugs fit in solidly too.  It comes with a short mini-USB cord and a basic, but decent set of earbuds.  No, it doesn't have all the bells and whistles of say, an iPod Touch (though some nice features)...but again, for the money I'm extremely impressed.  My Wife wants one for her birthday, 'nuff said.
4594027
A nice little unit for the money. I have spent a lot more and got a lot less with other units. The only reason I didn't give 5 stars is because I have to turn it backwards to use on my  Iphone, otherwise it is great.
3409387
Great product for the money. Set up was easy. Port forwarding was a little tricky. Works great. I'm going to buy three more. Free shipping was faster than I expected.
1796996
Features are great. I use the FM and Bluetooth most of the time.  The only thing I have a problem with is the display. It's hard to see on a sunny day.  The box is a little misleading, it has a MP3 logo but the tuner isn't compatible. Well worth the low price.
51202
Great phone/features for the money.  Using with PIAF and working great.  Speakerphone, headset, bluetooth all work great.
4449263
Good cameras for the money. Easy to set up and get going. I can't wait to add some Pro's to the mix.
1501087
Not bad for the money.

It's the perfect size for learning outdoors and has large visible LED lights which really help.

I'm still learning so, I haven't done a lot with it, but I like what I see so far.

The camera is not great, some lag, but there are upgrades.

Will do the remote mod to increase the range. Also, I have spare batteries which is a must.

I'm very happy with this purchase!
2704375
what a great buy.  For the money it does everything I need.  Great battery life.  Fast internet.
434478
I am a guitarist who writes and records a little bit if everything from acoustic to metal. Features are great for the money. I have recorded 4 songs so far and no glitches. Phantom power works well with my condensers and zero latency. Great product at a great price!!
990495
For the money, this camera works fantastic and had all the options we were looking for, doing them admirably well.
3499254
Nice features and easy yo use. I haven't explored all the features because there are so many but so far I really like it.