While I don't own one personally, all air with IR impacts. If in the market for cordless impact, after all the things I've heard and personal poor service from DeWalt, I'd buy the SnapOn and never think twice!
Two local salvage yards have SnapOn with druggie, changed weekly, lot boys using them. Never a problem, last time talking with manager one is over 5 years old with same 2 batteries going 8=10 hours daily!
While I never had a problem with my DeWalt cordless impact per see,,(had set of Dewalts, including impact,hammer drill,recip-saw,light and skill saw) may have been because regularly used reciprocating (sawzall) saw (use more than all the others combined to remove exhaust systems for replacement) damaged batteries faster than I could use them on impact! Dewalt battery goes up into compartment on tool bodies, which is fine on everything except recip-saw,,,,rapid back-and-forth motion inherent in this type tool would cause contact point of saw to wear the matching contact point of battery in two rather rapidly, RUINING the battery, as no replacement parts are available for battery itself. I've ended up giving my son all that yellow stuff, and started buying Makita, which has never given a problem in 15 years of corded chop-saw and cordless (home use)drill service.
Haven't even checked yet to see if Makita makes a impact. If they do one's on the short list of "to buy" items, if not a SnapOn may eventually over come my resistance to having different spare batteries and chargers setting about.
SnapOn doesn't have matching saws,drills, etc.
Bob