Installed it on both my iPad 2 and iPad 4. Both had plenty of space left and plenty of battery life. iPad 4 installed fine. iPad 2 is in constant boot loop. I'm using iTunes to run a "Update" on it that says it'll install 9.2 on it without wiping user data.
Just an FYI for those that have an iPad 2 still around.. be careful.
Just an FYI for those that have an iPad 2 still around.. be careful.