Mike, my grandfather bought his Paslodes specifically for that reason. He tried the compressor/hose thing and hated it since he does mostly sub work anyhow and nothing on a major framing scale, it was just a pain in the ass lugging all that around to frame in a larger opening, install new header, etc...
His sit in the truck probably 3-4 days a week most of the time and the framing guns only used once in a great while (the finish gun is used almost daily) and the framer works like a champ.
One thing you'll have to realize is once you break the seal on the gas cartridge there will be some minor -very minor gas leakage when it sits. So if your dont use the gun for a long time and only get a few nails out of it when you do, that will be the reason why. Kinda like my asthma inhaler, as I get older and hardly use it, it still goes dry from sitting.
Once you step into these guns you'll be very happy and wonder how and why you did'nt get them years ago, but you will be cussing a storm when they start to mis fire or dont do anything at all!! LOL, I find the most ideal time they quite working to be when we're setting trusses or doing some kind of heavy labor job when it needs to work....but they never work when you NEED them too

I just need to break down and buy a new set of batteries so they fit tighter and start getting on a more religious cleaning scale since I'm very bad at that until they stop working completely.
These gun are VERY rugged too, at least with my experience. I cannot tell you how many roof slides to the pavement they've endured cuz idiots on the roof dont know how to hook a tool, or else the tools fall off ladders or slip off tool belts...they just keep on keepin on so I'm personally impressed with that aspect of the Paslode tool.