I ride a BionX. I thought the regen/braking was pretty good. However, on a steep hill I still didn't have problem hitting 20mph on regen level 4. I'm 240 lbs and I was carrying a good 30 lbs of gear... add the weight of the bike, and we're talking about a 320 lbs load. I can't remember what the BionX user manual said about the max speed you should not exceed while in regen mode. I'm not sure what happens if you exceed that speed. Anyway, I converted my cantilever brakes to mechanical disc brakes... and the conversion did not play well with the regen braking, so I have completely disabled it. I use the disc brakes to stop... they do a much better job than the regen braking. I don't believe BionX, or any other manufacturer, intends the regen braking to be the main brake... especially on a steep hill. If you have concerns, I'd recommend hydraulic disc brakes. I'm not sure why anybody would have difficulty pulling a brake lever if they want to slow down or stop - I use the brakes in my car, I don't just downshift.