I really debated about buying the Blackjack simply because I'd heard negative things about the battery life of the phone.That being said, I found that if I left the Bluetooth off, it helped.But this battery makes all the difference. My last trip, I was sitting in the airport and checking email for hours, talking to people forever and the battery only hit the halfway mark. With the regular battery, I would have had to resort to the backup battery.It does add a little bit of thickness to the phone but not that much. Basically, the thickness of the camera section becomes the thickness of the whole phone. It still fits in my case.I'd definitely recommend this battery and cover.