I bought the ipad air a month ago and I started having the same issues as others (reboots, crash, etc).
After following this blogs and few others in English (I'm writing from Rome, Italy), I contacted apple with the will to return it, but the policy to do so before Jan 7th is valid only for devices purchased on line.
I bought mine in an apple store, so, after they checked that there was actually a problem, they replaced it with a new one.
One day after getting the new one (today) I am having the same issues of reboots.
Besides the problem, I was also surprised by the lack of the Customer care the Italian Apple is about.
I dealed with two disentangle apple store, the online assistance ant the apple care service and explain to all of them about this posts and a big number of unhappy customers around the world describing the same problems...the only response I received is: that I was the only apple customer in Italy describing this problem and returning the device.
I'm a new Apple fan, after using windows and other os for ages I decided to go all apple buying many of their devices in a couple of years (iMac, iPhones, iPads, iPods) and had very few problems....until now.
I am surprised I was not given the chance to return my ipad air to get the previous version instead...to wait for better release of the ipad Air next year.
I do apologise my bad English and for being that long, I'm so disappointed and frustrated about the issues and the lack of any reaction by Apple that I'm starting to question if to go back to other brands which are also at much lower prices.
I believe it is important to share this here.