You should consider the situations you're discussing before trying to apply them to each other.
With the iPad2, you're talking about an older device that was working well on the older iOS. Upgrading pushed the limits of its computing power and you saw a reduction in your experience. While not ideal, it's expected. It's part of why Apple stops providing support to older devices in iOS. With any more upgrades, the device won't be functional and you'd hate it even more. That's why you won't likely be able to upgrade it further.
With the iPad Air, it's a newer device. It's already having problems. Those problems, assuming you don't have some random apps draining your battery life, are related to the hardware or the iOS. If they're related to the hardware, you likely have a bad device that you should take Keith's advice and visit the Apple Store to discuss. However, their first troubleshooting step will be to restore the device as new and see if the problem persists. This checks to make sure your iOS installation is clean and there wasn't anything else causing problems.
In terms of losing things, it sounds like you're running iOS8 on the iPad2 and iOS7 on the iPad Air. If any apps require iOS8, they wouldn't install on the iPad Air so I'd expect you'd have an app or two that wouldn't transfer from one device to the other. You can check that by opening the App Store on the iPad Air and see if you can download the app manually. If it tells you the app isn't supported, you'll have your answer.
02-12-2015 09:42 AM