My favorite aspect of these shoes is the toe box. I don't have narrow feet, especially not my toes and most shoes tend to cramp my pinky toes. I then need to have a rotation of different sizes so later in a race I can go to a bigger size to fit my toes. With the M2s I can tighten the mid-foot enough to stay tight and the toe box is wide enough to accommodate even my pinkys without having to go up too large in size. No more changing size shoes after 50 miles!
The M2s have a 4 mm drop height, but the taller stack height means they have more cushion for repeated impact than a lot of other minimal shoes. These are certainly not minimal shoes, which is why I like them so much for 50 and 100 milers, but they also don't feel like you're wearing tanks. I like this balance especially for long runs. Some people can do minimal shoes forever, but I want a little bit of cushion and support without feeling like I'm bringing the kitchen sink along for 50 miles.
The soles are a good combination of not too soft not too stiff. Too soft and I feel like every rock I jump over is digging into my foot, too stiff and I don't feel like I can feel the rocks at all. I like to be able to feel the terrain I'm running over. The tread is pretty good in most conditions, but it really doesn't fair too well in mud. And I've also noticed some slipping on dry dirt, but that's hard to avoid as you come around a corner especially on Front Range trails in the heat of the summer.
I also like the mid-foot support (hence the M) as the longer I go the more support I tend to need. I have weak ankles and the extra support helps on more technical terrain and the more tired my legs get. Another reason the M2s are my go-to for anything over a 50k.
My only real complaint has been the durability. I put close to 700 miles on a pair of shoes before they need to be replaced. The M2s tend to last me 300-400 miles. The upper mesh usually starts to fall apart after 250 miles, although since they dry so fast and are so breathable this is hard to avoid. The tread and sole cushioning is what is all but gone after 300 miles.
There aren't many shoes that you can slip on for the first time and head out the door for a 20+ mile run without blistering. The M2s have been able to handle that and more. They promise to be my long distance training and racing shoe for a long time to come.
Week August 4 - 10
Miles Running: 41.5
Hours Hiking and Running: 9.5