The rotor crank thing is interesting - but it's a solution looking for a problem. People who benefit from them have a poor pedalling style - they'd be better off spending time on their bikes with a coach and a bike fit expert and learning some 'suplesse'.
I was chatting with magnus backstedt last summer in my LBS about the rotor rings & he was raving about them (used a normal round outer). what comes around I suppose...(pun intended)
.. personally I always hated biopace or any version of it.
Funny thing is , newer version still try to eliminate the dead point ( dont know how to translate this , the point where none of the legs work ) , we called point mort in french .
Biopace is a bit like riding a bike on a bad acid trip.. You legs feel wrong cycling in a pulse like cadence.. I had a even worse spin off on my first ever mountain(ish) bike. A Raleigh Massif with 'Ovaltech' chainrings.