I'm 72kg and tried a Rise H15 recently in the UK's Lake District.I rode 50km and over 800m elevation, conservatively at first in eco, then started using more trail and some boost mode but turning it off on some flats and downhill . I finished the ride flat out in boost for 15 mins including...
Having tried a number of EMBs and been put off by the drag over the speed assist limit I rode a demo H15 last weekend and was very impressed - The motor was very quiet, I didn't hear any of the slapping I've read about and I no issues with drag, it felt very free.