wouldn't expect the upper to degrade with only road use. it's the impact with trail debris, slopping through mud, crunching through ice, etc., that shreds montrail masais so badly, a problem i've not encountered with my inov-8s or any other trail shoe. for what it's worth, the f-lite 300s (and presumably 250s) function well if one has to put up with a bit of road on a trail run, but the luggier models (e.g., 285s) have no underfoot give. the 285s do, however, do well in grass, mud, and other soft terrain (presumably sand). seems to me that the NB 790 would perform quite well on roads or crushed rock/wood chip trails, as well as more technical surfaces.