Hi ... I have an original iPad1, and an iPad3. Battery life on both is excellent - I think my iPad1 gets nearly 10 hours still; my newer iPad3 seems to get ~10 hours. And for most ways I use it, they really do go down at about 10% per hour of "ON" use.

If you play outdoor gigs and need to turn the brightness way up (which I've done), expect the battery life to be somewhat less ... but I've never had a problem getting through even the longest gig with either iPad.

Jim