I'm re-doing my basement and building a garage/fence/deck next spring and maybe more. I will be getting a Paslode F-350s Stick Nailer, F-325C Coil Nailer and want to be able to run them at the same time.
CFM delivery is the most critical thing in air compressors. You don't want it running all the time, and the CFM rating is a function of how good the motor is at re-filling the tank and keeping it full. A big tank is a plus too.
Of those three, the 15 gallon DeWalt is a no-brainer in my opinion. If you want to be able to run multiple nailers at once, that's your best shot. The others would do it, but not quite as well.