Whatever you are building, I think the pneumatic squeezer has to be the second best tool after the tungsten bucking bar !
There are just so many places that the P squeezer is better, whether it is nutplates, dimples, rivets, thumbnails or whatever ;-)
As I said earlier, the ability to release the die set back into the squeezer is important. I bought a refurbished squeezer from The Yardstore some years ago, but that said.......
My buddy bought one recently - a new one with no release button and the dies would not fit. Yardstore were most unhelpful in dealing with him, he solved the problem by buying an adjustable plunger from Cleaveland Tools.
I would not use Yardstore ever again - good customer service is free or cheap and helps us all, theirs was not and doesn't.
To summarise - look for a nice old refurbished unit with no safety guard, a releasable plunger and as Sergeant Phil Esterhaus always said...
Let's be careful out there !