Just as a data point to add to the thread... I went from 3/8" to 90/75 and felt the edges were almost exactly the same, maybe more bite leaning towards 3/8", but just barely. The glide however, was like night and day. Way smoother with 90/75. I can glide a whole lap or more around the rink. I'm 140lbs and play in warmish Norcal rinks.