Brilliant shoe. I have over 400km on mine and the cushioning feels as-new. Love the smooth, fast transition - they definitely get me onto my toes quicker and make it easier to increase my cadence. In comparison my Kayanos and Trance feel slow and dull.
I have a pair of MR00s for casual wear and gym use (as a strengthening tool). The sole is already wearing fast - and irregularly. It is part foam, part firm vibram rubber. The hard vibram rubber is virtually untouched but the foam is already wearing away. Thing is, the entire medial part of the heel is just foam and that section is wearing down - so they will then force my foot into a pronated position. Dumb, dumb, dumb design, New Balance.