I had dewalt stuff from the time that my father gave me a few of his dewalt tools, so I stuck with Dewalt, eventually adding some of the newer 20v tools and a few brushless. About 4 years ago all of that stuff was stolen (along with all my air tools... GRRRRR!!!) So since my house insurance paid for all of it, I decided well, might as well try a different brand, since I have no reason to stick with Dewalt.
I chose Milwaukee. A drill, a small impact driver, a larger impact, some flash lights, sawzall, and so on.
IMO, brand doesn't really matter, just pick one. I like the Milwaukee stuff, but honestly I don't know that it's any better or worse than the Dewalt stuff (except for the older 18v dewalt stuff, but that's older technology) The only thing I think I don't like about Milwaukee, is that it's more difficult to remove the battery with one hand. Not that big of a deal, but yeah.
On the air-tool side of things, I replaced all my stolen stuff with Aircat and a few SP air. And THAT, I can highly recommend. Aircat and SP is nice.