like I have said a few times I think the hardware is going to be spot on and few to little defective units, when you mass produce at this level a few unit with problems are expected.
However the only real concern I have is the os software, as it is new and untested I do expect it to be semi problematic with quite a few updates coming in the first year I wont be surprised if were at v2.01 by nov 2014
but like shoes said, "day 1" without a single fuck given