I work in a shop were air tools are starting to dwindle in popularity use and the cordless tools are starting to take over. There are 2-3 guys that are split with Matco & Snap-On guns, but the rest of us have settled with the Milwaukee Fuel impact wrenches.
I've got this:
18-volt M18 FUEL? 1/2" High Torque Impact Wrench with Friction Ring tool only | Milwaukee Tool
It has 1100 ft-lbs of breaking torque and 700 ft-lbs of fastening torque. Works real well and the batteries are long lasting.
I've had Craftsman tools and while I've never really broken them, the batteries were always crap and the bigger cost item of the tool is always the battery. I'd rather have a battery last forever and the (cheaper) tool wear out. One of the best items I ever bought was one of the original Bosch Impactors over 7 years ago. A little tired, but still runs strong and the batteries still work just as well from day one.