When it comes to bikes I am not too much of a DIY-er. I choose Bionx primarily for the bionic feature - you don't really feel like you are riding on a motorized system, it's just a bike that goes faster.
I sporadically read about failures of the 500 W Bionx but I could not find any evidence that it's a bad design for what it does. The dealer has suggested that I get a 48V battery which may alleviate the heat issue but, again, I heard mixed stories about the the 48V battery+ motor combination. Actually, I am not even sure if the new 48V batteries are designed to work with the 500W motor.
But regardless, has anybody around here used the 500 Bionx motor?