So I was about to post a new thread on this for my roof raise, but since this one is up I'll use it.
The Harbor Freight is a good one if you plan to use pop rivets or simple steel rivet removal.
I'm planning to use all Steel rivets and the Harbor Freight one will not suffice. I've been heavily researching riveting lately from multiple sources.
If you want an air hammer to drive in traditional steel rivets, the cheapest one I can find to do the job is the Aircat 5200-A-T Long Stroke.
Here is the science for those interested in learning. Lower BPM (Blows Per Minute) typically are for Destruction purposes, and High BPM are for cutting and separating. Lower BPM will in some cases have a longer stroke, but not always so don't be fooled by the label "Long Stroke", it still may only be 2 5/8 inches long which is NOT sufficient to smash and compress steel rivets.
At minimum you need 3 3/4 inch stroke, and the cheapest I can find is that Air cat at $112-$140 depending on where you buy. From there they jump to $320 for HRH-4X, and up to $610 for the Matco 2916 for the same specs. The Matco is shop grade and should last you forever, if you are just doing a few jobs the Aircat will suffice.
People who retired from the Shop industry stated they used to have longer than 3 3/4in stroke models but nobody uses that much power anymore so they stopped making them, and it's getting harder to even find 3 3/4in stroke models now because they aren't requested as often. People are mostly buying High BPM models for shop use.
But for a roof raise you want at minimum 3 and 3/4in stroke to smash those steel rivets in properly and a heavy duty bucking bar if doing Steel rivets.
If you are doing Aluminum Pop-Rivets, just go with a Harbor Freight riveter. For Steel you don't need a riveter at all because you can just use the Air Hammer and bucking bar to smash/compress. It's a different technology.