I have never used the CP717, but do own 2 Snap on air hammers. PH3050A and PH3050B, and they have never let me down. Instead of buying new you can try ebay and CL they have some great prices on there.
Used a ph3050 once, wasn't impressed. Could have been that particular gun, don't know.
However, my matco mt2816 does one of three things.
Move what I want it to.
Break whatever I want to move, or whatever is near it.
Break bits.
Everyone in the shop hates when I get it out. Its my favorite tool though. Something neat is going to happen when it comes out.
I had the IR118MAX - and it worked great, for a while. The thing worked less than 4 months of occasional use. It started "stalling" the anvil after a month or two, then it got worse and worse. Very disappointed in IR about that air hammer. Plastic internals, glued together.
I bought a Snap On on ebay it it is awesome. It's what I should have bought in the first place.