Pretty good actually. If I hadn’t installed IOS10 on the ipad4 I was going to have to do a restore as i was having trouble with the password screen locking up and not letting me enter the password. Maybe the backup problem was a corrupted software glitch in ios9. The trouble seems to have gone now.
I did a complete download and install via iTunes. Overall very happy with the upgrade, although my iPhone 6S seems to have a lot more fun with features and making me think I need to convince work it is time for an upgrade when the new iPad Pro comes out.