I can not commit on how picky either place is on returns. With xmas you are lucky because returns are good till near the end of Jan. Normal for the NB is 14 or 15 days ask when you buy.
I will most likly be returning my NC in Jan. I'm not happy with frame on the front and how the glass meets the plastic where the N button is. That plastic is bowed. Over all its not a bad device, it really could use a little over clocking and a nice launcher or Rom. I just want to see what develops in the next month.
So far the NC can be reset with a fresh load of the firmware by holding down the volume down and power buttons at power on. So this should lesson the chances of bricking. No one has unlocked the nvram yet, so imagine that restore is a pretty good failsafe.