I recently got an Air 2 refurb as I needed a higher capacity and it replaced my Air. I'm super impressed with the upgrade. There is that vibration thing but the iPad speakers are not really my preference for playing music or audio from video.
As the display seems to be almost flush with the bezel it makes dreading far more comfortable on the eyes. That's probably not the best way to describe that but I've noticed such a difference that the Kindle probably won't be coming with me on my next flight.
IOS 9 on the Air 2 is massive. That alone is enough reason to opt for the Air 2.