I restored my new iPad from the backup copy of my iPad 1. Everything seems to be working, however, I've read a few comments where this can cause issues.
What did you do, restore or set up as new, and why?
If it was a backup on iCloud, your fine. If it was a backup on your computer, you have chances that the software may have been corrupt and with restoring from that back up its corrupt files come to the new one.
So what software was on iPad 1 and what kind of restore did you do? iCloud or computer? The iPad may seem fine now, but I'm if you see some random or frequent crashes occurring every now and then. Those issues may lay dormant for some time and start making themselves apparent on whims and to where they happen all the time.
If you want my in my opinion, if the iPad is fine right now, I wouldn't worry about it. But if you experience freezes, hangs, crashes, reboots, apps won't open, features in apps disappear (+ in calendars, volume bar in YouTube or iPod) then you need to DFU and reinstall 5.1 and start fresh to keep those bad files away.
Here this has helped you in some way, PM me if you have any questions or just post here I guess haha
*Note* Those of you reading my post and have experienced the issues I mentioned, here's some more info.
1. If you're store from a computer backup the files can be corrupt so a fresh install and setup as new iPad is needed.
2. If you have an iCloud backup of your device that is from iCloud, then simply, DFU, reinstall software, and restore from iCloud
Remember I mentioned earlier that
**In other words, computer backups can contain corrupt files and iCloud backups differ as they can NOT contain the corrupt files. So when in doubt, use iCloud! haha
Ok I'm done.

loll