My gold 128Gb Air 2 came yesterday and, so far, it seems just about perfect. Display looks good, consistent lighting and a noticeable improvement on the Air I was using (these are work devices btw, wouldn't have paid for the Air > Air 2 upgrade as I was happy with the Air). Touch ID works well, though it doesn't seem quite as consistent as my 6+. Maybe I just got a slightly off scan the first time through.
To be honest the only thing I'm not 100% happy about is that there's a noticeable vibration through the case when using the speaker. Side effect of having such a thin device I guess and I'll get used to it but pretty sure it's not a flaw in manufacturing, just a factor of the design. Doesn't distort the sound at all and, to be fair, the quality of the sound is pretty good for an inbuilt speaker.
Oh, and I'm really glad I went with the gold... boy does it feel weird to be saying that. Not a fan of last years gold iPhone but the change in colour for the iPad coupled with the white front works very nicely indeed. Definitely prefer it to the silver / white combo I was using last year, especially with the small gold ring round the home button. Just feels like a bit more of a contrast while still being complimentary and it's a genuinely nice colour on such a big slab of metal.