I'm a Ryobi guy. I'm a hobbyist/diy guy, I don't use them professionally. I went with them for 2 reasons:

1. bang for the buck. I want a good deal, I went something that's going to do anything I can throw at it. My first tool was a 1/2" impact wrench rated at I think 1150 ft/lbs, for about $220. That's as much as you'll ever need unless you're working on semis, and the Milwaukee equivalent is probably $600. I also got a hammer drill for $100.

2. I'm pretty sure they have way more tools that use the same battery than anyone else on the market. My favorite is my soldering station with temperature control, but they make everything!