I've been watching for a good 1/2" drive cordless impact far around the farm for a few years. I have a couple cheap 1/4" Ryobi's which are handy for little stuff. I'd been hearing good reports on the Milwaukee Fuel impacts (they make different versions) so when they went on sale I finnally got one. This Millwakee (27632) has torque rated at like 1100 ft/bs break way and 700lbs tightening. I got the kit with 2 batteries. Since I got it I haven't used the air impact since around the shop. At the same time I also picked up the 5" cordless angle grinder (tool alone) which works well too. Both seem to be well built products.
Angle grinder
Angle grinder