they have 100, 1000, and 2000 miles on them.
notice the hole underneath the big toe in the most worn pair.
of course, i have some insoles in there to run in those ones, although they are now relegated to slow runs of less than 3 miles.
i started wearing racing flats because it is hot in georgia in the summertime, and my old shoes (and socks) held the heat in really well. i got to hating hot feet, and i found some light weight shoes on the clearance rack....tried them out, and found that the light shoes also have very breathable, light weight uppers. perfect for shedding heat. i also started wearing my shoes a half size too big, so that there was more room for air to circulate inside the shoe. along the same vein i stopped wearing socks. now i am so used to them that i wear them the same year round.
i wear these shoes with just the included insoles for about the first 250-400 miles, then the EVA is sufficiently compacted, and the upper stretched enough, that i put in spenco insoles. usually a 1/8" thick insole.....then after 800-1000 miles the shoes are compacted even more, and i switch to a 1/4" pair of insoles.
i am on the original 1/4" insoles still, these things last forever....probably have 3000+ miles on that single pair of 1/4" insoles.
the only thing these shoes aren't great for is trails with sharp rocks, at least when they are really worn. that being said, i raced mountain mist in them this year, and since i was running hard and concentrating on the trail, they were ok.
i would not want to run a trail race longer than 50 miles in then, because after 50 miles i would rather have more padding on the feet than light, breathable shoes. more padding so that when i am tired i don't have to concentrate so much on foot placement.
on roads i wore them for the mother road 100 (at least the last 80 miles). and i wore a previous version (the NB RC 550's) for more than 200 miles of the vol state 500km a couple years ago.
i've still got a couple pairs of these stored under the bed, so it'll be 2011 before i really need more shoes, especially is these MT100's work out well for some trail running.
initial thoughts on the MT100:
that rock plate decreases the flexibilty of the shoe significantly.
i use a razor to slice the shoe in several places, and regain that flexibilty.
i've done this to many shoes in the past, and it doesn't cause them to split like one might think.
after a few more runs in the MT's i'll post again on that.
