some of my mountain biker friends did share with me that their personal view of ISIS standard, sucks over square taper anytime. if i remember correctly, it was either square taper, or octalink; external bearings might come before ISIS.

for one, i'm convinced by the Rotor SABB - external AND self-aligning. revived my aluminum MTB which i'm using as a tourer by slapping on a rear rack - and ride occasionally offroad as well.