I have both Milwaukee and Dewalt, both 18V. Used every day by employees for a number of years. All still work great, which is surprising due to some of the temp guys.
Only thing I don't like about the Milwaukee is the replacement battery price. It's ridiculous, but they do last quite long.
Dewalt's have pretty good torque, and battery life, as far as how old it is, is really good. Battery run time between charges is pretty poor compared to Milwaukee, but swapping batteries is quick.
On the really down side with Dewalt. The keyless chuck is junk! If you use a drill to run tap's in steel, forget it! Besides, they rust up pretty bad when exposed to humidity. The clutch is a bit funky also.
The crappy chuck is the reason why I'll never buy another one.
