This is only my opinion, and I'm opinionated: ANYTHING but the Dewalt. Dewalt quality goes downhill daily as the company (Black and Decker) pushes further into the home hobby market. Their new drills lack the power of the old ones and the batteries are utter garbage.
I favor Milwaukee. They're not the Made in the US company that they once were, my drill is made in the Czech Republic and battery in Japan.
And it weighs enough to anchor the Queen Mary. New batteries are reasonable, for 18V, and it has incredible power, after a few years of abuse in a lot of rain and a new set of brushes.