I-R or C-P impact wrenches are good, but I personally see no need for one other than in a production shop. Now there are 3/8" drive air ratchets. They can be very helpful when installing a lot of fasteners.
Regardless of which pneumatic tool you use, an oiler on the line or as Bill says, a few drops of
oil--Marvel Mystery
Oil--before you use it each time, will ensure a long tool life.
A 15 hp two-stage compressor with an upright high-volume tank is best if you're going to use a lot of air.