I really like the Altra shoes. When I run in a traditional running shoe I run rather flat-footed. I've been running in Newton's for 8 or 9 months now but I still tended to run flat-footed unless I really concentrated on landing on my forefoot and on my form. In the Altra's I naturally run as if I am running barefoot in the dojo (which is a close as I care to come to real barefoot running.) I'm landing on my forefoot and my feet and body are properly aligned without having to think about it and make a lot of corrections.
One major caveat to anyone considering switching to Altras: take your time. I have been wearing high heels since I was in middle school (okay, let's not start the mental math to figure out how long that is, just suffice it to say that we called it "junior high" back then) which means that my body has become very accustomed to unnatural positioning. Running in a zero drop shoe will stretch the back of the ankles and lower calves. I have experienced some tenderness there and in my arches even though I am tranitioning from the Newton's. My plan is to run no more than 1-3 miles per day until all the tenderness is gone (it's getting better pretty quickly.) This is a good time of year for this since I don't have another long race planned until the fall.
For all the Type A runners out there who can't imagine cutting back that much I recommend that they run 1-3 miles in the Altra's then switch to their regular shoes for the remainder of their mileagle until they've adjusted. Oh, and one other thing, the first time I ran in these shoes the toes in my left foot got a little numb. I changed to the alternate lacing pattern on the Altra website and that took care of it just fine. It's not the shoe, it's my high instep that is the problem. These shoes have plenty of toe room. My tootsies feel great when I run.