I'm not sure if I'll update to the new OS ASAP. All these years of MS upgrades has made me wary and this is my first experience with Apple.
I would imagine it's pretty difficult to brick this thing since it's basically running an iphone operating system. Worst case you do a complete restore and it's factory new. With that said, I've never had any issues with apple's fw upgrades. Can't say the same for microsoft though.