Still being able to receive iOS updates doesn't necessarily equate to good performance. Just look at all those folks complaining that Apple should allow downgrading because the latest iOS update made their iPad run like crap. The iPad 2 may have gotten until iOS 9 but I personally wouldn't update it past iOS 7.Still fast and not a big difference compared to the Pro.
The air 2 will be like the iPad 2, last a while.
That said, I think the iPad Air 2 would fare better than the iPad 2 in this regard. Imho, the iPad 4 and newer have aged more gracefully than the iPad 2.