I'm looking to upgrade my air compressor. Currently I have a 4gal dual stack Campbell Housfeld that has served me well. But it's not all that powerful, leaks air, and is annoying to move around since it doesn't have wheels or anything. It works, I'd just like something better.

So it would make sense to get a big tank "shop" compressor. I do have a decent sized shop and could probably fit it in. But we have a tiny house with no storage space, so a lot of stuff ends up in the shop as overflow. I guess what I'm saying there is that I try not to waste space.

I'd like to have at least one portable compressor so I can haul it over to friends houses to help them with nailing or whatnot. But the one I have does serve that purpose.

My question is, if CFM numbers are similar, what reason is there for a big shop tank compressor other than the fact that the compressor won't have to run quite as much? I can get a Dewalt refurb 4.5 gal high-output compressor for $230 that does the same CFM as the 20-40 gal big tank ones in my price range. While it would have to run a lot more often, it's also a lot smaller and has wheels for transport.

In general, my compressor use is mostly for framing/brad/finish/etc nailers + random use of impact wrenches, die grinders and whatnot. I'd like to be able to use a spray finish setup at some point in the future. But that's a ways off and I don't have anything set up for it at the moment.