Decent battery, when it charges
354843
I got this battery a few days ago, let in charge for a good 8 hours and it only charged up to 50, I've only got it up to 100 once, and it still barely lasted me the day, if I was you id save my money
1795232
After about two months, the batteries have settled down and have decent enough life, but seems to have dropped a little bit from the first time they are used.  I have two Neato's (upstairs and downstairs) and it seems it needs to charge at least once at the end to finish.  I'd say each one is doing 800 sq feet (have a 1800 sq ft house, but some rooms are closed off).

But so far the battery packs don't seem to be faulty.  Like any battery packs, sometimes you'll get one with a faulty cell and the performance drops like a rock (had this happen before with another vendor).

So again, decent battery life, but not really a big difference with the stock batteries it seems.

I did get a couple of responses from the seller to make things right and if I wanted to return or exchange the batteries.  I added a star because of their customer service and willingness to fix things if I though these batteries were shot.
2819720
Works, but doesn't hold a charge well, have to keep it on a trickle charger or it dies in a few days
2252109
I have owned this portable battery/slate for a few months now and it has served me well for a little over two of them. On its last run, I left my 3410mAh phone plugged into the fully charged slate for around 6 hours unattended. The phone was at around 30% battery when I left. Once I came back, my phone was only up to 80% and the portable battery appeared to be dead. I was able to recharge the battery back to full (all 4 lights on) but it won't charge anything and the lights won't come on when the button is pressed. There are batteries for half the price with twice the capacity that actually work. I will not pay as much attention to appearance and form for my next purchase.
4793244
Ok, but does not hold a charge as long as the original.
1633350
The battery is fine I charged it and it worked OK. The only downside was that it was quite warm after charging for an hour./
3523973
It holds the charge, but the issue I had using this battery was that when my laptop (Lenovo W500) shows 18% battery remaining, all the sudden, it turns off!!! By that account, 18% charge remaining, I should still have at least 15 minutes battery left, but unfortunately that's not the case! I never had this issue with any other battery brand. The estimate showing on laptop was always reliable. I understand that fluctuates with usage, but with normal use, such as just typing a document, it should hold up. Also, do not expect a full charge to give you a couple of hours. In the beginning, after full charge, you may see the message that you are good for an hour and 20 minutes, but in reality it discharges in less than 40 minutes, and shuts down, even with minimal use, such as typing a document, with medium screen brightness!
133239
I have mixed feelings about this battery. Sometimes the computer has issues with the battery and it needs to be removed and reinstalled. The battery otherwise operates properly.
2474744
I bought this battery for an old phone that I needed to last for a couple of more months, so I took the chance and bought this very low-priced battery.  It works for me and I'm happy I bought it, but it only lasts about two days between charges.  So if you buy this battery, don't have high expectations for it.  It's a good backup battery, though.
1281624
This battery definitely holds a charge.  My wife has already used the cordless phone for a two hour phone call and had plenty of charge remaining in reserve by the end of the call.  I think spending a few extra dollars for the name brand made sense.

EDIT 8/29/2012
I have ammended my original review and knocked of a couple of stars.  Although I've had the battery for only a little more than a year, the battery will now only hold a charge for less than an hour.  I did buy this battery again as a second replacement battery, but I wish that it could perform at peak capability for more than year.
150278
Doesn't last nearly as long as OEM battery, but that's to be expected. What's not acceptable is that it runs out of power without warning, even when it allegedly has plenty of charge left (>20%). This forces me to remain paranoid about monitoring the battery life, searching for the nearest outlet as soon as I see it dip below 50%, which gives me about an hour of usable battery time. I've had it for less than a month.
1721314
First, the battery life is up to par with the original Apple battery (when it was new) that was replaced, and the battery itself works fine and holds a charge fine. Also, the toolkit it comes with is nice and makes it easy to install.

There are some issues with the battery though. First, there is no instruction manual on how to replace your battery or what it should look like. Just 2 screwdrivers labeled 1 and 2. So, you have to go to youtube to find an instructional video on how to replace the battery.

Second, the battery seems to be maybe a bit too large? I re-arranged it a few times and it didn't have much of a difference, but when you install it, you will notice that your track pad will feel very hard from the sides to the top. This means you can't actually click in those areas or you have to press really hard to left click. After re-arranging it, it got a little bit better, however the issue is still there which is pretty annoying to deal with.

Edit: I would recommend buying the battery. The customer service was outstanding, and they sent a replacement battery for free. They actually took the time to follow up every step of the way, which I don't think I've ever seen a company do. After I got the new battery, I sent back the old one. The new battery, at first had some issues fitting into the case, but once I was able to fit it by pushing pretty hard, it worked. The track pad issue is fixed now and the battery holds the charge just fine.
1322031
This charger is nice when it works.  Really, I don't have much to say beyond that.  The controllers fit on the cradle well enough but sometimes you have to move them around a bit if you don't have them on perfectly.

My issue is that sometimes it just doesn't charge.  I've made sure to seat it in the cradle and then press down somewhat firmly to ensure a connection but there have been far too many times when I've grabbed a controller off the cradle only to find out it didn't charge.  Perhaps about half the time.
4368508
After about a year of use, the battery stops holding the charge.
1581527
When it works, It works pretty darn well.

Like i said, when it works...

After charging overnight it ran for about 5 minutes and died. After charging for 2 hours you get about 1.5 minutes of use - and then it dies again.
2285222
I was happy to buy it at this price. Sometimes the charger is is not charging, just staying at the same level. After a month, my battery dies within two hours of being unplugged without watching videos or being on social media. I'm going to have to buy a replacement battery.
1520726
I was offered this external battery for Christmas a few days ago.
I've left the battery charging overnight the first time, and the 4 leds were on in the morning.
I've used the battery in the train to charge my phone a few days later, it was OK.
It seems that now the product won't charge past 90% (the 4th led won't stop blinking), even if I left the power adapter plugged-in overnight.