I used Air Tech on a prior recover and thought it was about as easy to use as you could ask for. The glue through primer was actually quite fun. IMHO, the paint is also pretty darned friendly provided you adhere to the instructions and a few friendly suggestions from folks like Kenny Blalock or Steve P. I did not end up with a "show winning" finish, but almost all of that was due to prep and not the paint. It was still a very "pretty" cub.
My experience was much like Gregs. After only 2 years I had cracks on the top stringers on both sides from leaning into the plane while moving it. And rock chips on most of the metal surfaces...After a hail storm the airplane had to be recovered due to many holes, but,, even with out the holes it would have had to be recovered due to the amazing amount of ringworm from the smaller stones... I am certain none of that ringworm would have shown up on a recent dope or Stewarts job...
I worked a Thrush that had Air Tech professionally done. The paint on the tail would de laminate from the primer and come off in sheets...
I recovered the cub in Stewarts, Like Greg I would never cover another "bushy" or work airplane in Air Tech again... Too bad because it really does look good...
If you are thinking Stewarts paint is going to be any easier than Air Tech... it won't. Clean up etc will be easier, but achieving a glossy finish (if that's what you want) will be twice as hard. It will still come out very nice, just not as shiny as Air Tech. The good news is that so far it seems to be amazingly flexible... I have inspection hole cut outs from the Stewarts, and the entire skin from the Air Tech and the difference is night and day...
If I were recovering a J3, and was not going to be exposed to the chemicals on a daily basis, like a professional, I would borrow an air mask, and use dope, polyfibre, or some such... Some wheels just aren't worth re-inventing...
Take care, Rob