I have the iPad Air and just got the Air 2. The reason I didn't get it before was because I was happy with the Air and thought I'd regret buying it. Here are my impressions...
I liked it a lot, I didn't expect the screen to feel better to the touch (less plastic) and the laminated display makes everything look different, not much better, but more immersive and alive, I really liked it.
sound isn't as good as the original Air, but it's okay for something this thin, and it vibrates when the speakers are loud, but I can live with that too. Battery feels the same, it's hard to tell because I've been gaming a lot.
So far I didn't find any game that would make use of the new A8X. Most games always ran good enough on the Air, but Everything runs smoother, games like The Wolf Among Us, Civilization Revolution 2, and XCOM are a joy to play. Also, I'm an addicted Hearthstone player, and on the Air there was a huge risk of switching apps for a moment and the game shutting down, now it feels a lot better since it has 2GB of memory.
Screen uniformity is good, this is the best screen that I've ever had on an iPad. I don't regret buying it, and I'll keep using the Air as well, but if you are a gamer or simply use the iPad for things other than web browsing, you are not going to regret, because this is much more future proof than the original Air. Now yes, I'd be happy with my original Air if web browsing were the only use for it, cause the Air 2 is a beast and the Air is still going to run everything pretty well.
Oh well, I love this iPad Air 2!!! :O now if you have the money, forget common sense and just go buy it because you won't regret this decision