I like IMP1000
ipad 2 battery because of the following reasons:
1) So far this is the best portable battery for ipad and my other electronics device because the performance is excellent. I can charge my iphone until the battery full for several times. Other batteries that I tried before, lasted only for 1 time charging.
2) Unlike batteries pack that only serve as extended batteries for iphone, IMP1000 also charges the iphone, just like you charge your iphone to a wall outlet.
3) I use IMP1000 not only for iphone but for blackberry, wifi modem, ipod, even portable speakers.
Iphones are amazing invention but the biggest weakness is the battery performance and New Trent has provided solution to cover the weakness, great job!!!