I upgraded from Air to Air2 about a month ago. I've never heard a popping on mine. I've seen a video with the screen distortion issue. I keep mine in a hardshell case but I tried to duplicate the issue when I first got it and had no screen distortion.
I agree with Max(IT): the sound of the internal speakers resonates (more bass frequencies) but doesn't distort. I preferred the sound of the previous model, but it's not terrible by any means.
The battery life of the Air 2 is shorter than the Air 1, but it also has a significantly faster CPU and more RAM. The 64GB Air2 is also the same price as the 32GB Air1 I bought a year earlier. Double the processing power and double the storage space for the same price is a win for me.. so I'm glad I sold mine and upgraded.
I don't care what these figures say about the iPad being the weakest link in the tablet market, because I know it's one of the best tablets on the market and they aren't going anywhere anytime soon.
Sure sales are down for various reasons. However the iPad is the single best selling tablet on the market by a long way. I upgraded from the air 1 to 2 simply because I wanted more storage space. I bought the 32GB model last year. This time I bought the 128GB for only £80 more than I paid for 32GB last year. So for £80 more I got 90+ GB of storage, a faster CPU, more ram, a better camera, a better screen, a lighter device and a gold finish. Now that I have enough space I don't plan on upgrading any time soon.