I used a Neo-air on the AT last year, with no problem, but it developed a leak shortly after. Still, not bad getting 2000+ miles out of a light inflatable. I patched it, but didn't trust it enough to start the CDT with it this year. I certainly will use it for trips where mileage is measured in up to the low hundreds rather than thousands of miles.
Anyway, as a result I started this year with my wife's (new) Neo-Air, and for whatever reason it developed a very slow leak along the way, and I literally just got a third one to do the latter half (?) of the trail. No problem with that one, it's in good shape. Testing literally today I can't find the slow leak on my wife's neo-air, and I was pretty careful. In contrast, the leak in my Montbell pillow was easy to find today (that developed only after perhaps 4000 miles of trail use); it's right in a designed crease, so I'm not sure how well a patch will serve there (TBD).
Okay, sorry to ramble but my very tentative conclusion is that despite being a lot of mattress for not a lot of weight, a Neo-air will hold up very well for more limited (sane) use, so long as reasonable care is taken.
These comments certainly don't fit with the "most durable inflatable air pad" title of this thread. However, I personally wouldn't be interested in the "most durable", as I imagine it would be heavier than I would care for.