Square tapers imo are superior to isis in many ways. for a start if your cranks do happen to come loose and you don't notice instead of being f*cked for ever all you have to doo is tighten them more so the crank is pushed further up the taper and they will be tight as if they were new again. With isis because the splines are nto tapered this cannoty be done and you will have a £140 set of paper weights (inthe case of middleburns. Also ISIS bottomo brackets all seem to have the shittest bearings ever, all my mates with ISIS cranks are constantly moaning about their bb's being shit and borken in some way or another. I have never had an idduse with any of my square taper bb's. Square tapers don't round off unless your are a complete Moron and don't tighten them up, this doesn't have to be done often either, maybe once every 3 months at the most and they will be fine. get square taper, unless you enjoy paying more for aninferior product, that is likely to break sooner and irrepairably.