I've been really happy with my Milwaukee impact driver with the M18 battery. Often, I can't believe how long it's been between charges on the battery.
I have a jigsaw on the same platform, which never worked right: sent it back to Milwaukee last month, and they fixed it under the warranty. Just bought a drill / hammer drill with the same battery platform, and have been loving it. Made super quick work of boring 4" deep 5/8" holes into PT 6 x 6's last week.
My sense is that battery life / price and customer service is the biggest deal. I love my red tools, but if I had to reinvest in battery-powered tools, I'd probably go with Rigid, since I can get a replacement / exchange at Home Depot on the spot, instead of having to do a few hours of calls / running around to get my Milwaukee serviced.