I had cantilevers on my touring bike that I converted to an e-bike. The canti's weren't really very good prior to the conversion. The added weight of the conversion made the canti performance poor. Add some rain to the equation and the canti's were scary and dangerous. I had a frame builder add disc brake tabs and disc brakes (avid BB-7 road) to the frame. Huge, really HUGE... improvement. If you're looking at buying an e-bike that you like and it has discs... I'd consider it over any e-bike that doesn't have discs (well, maybe I'd consider some hydraulic rim brakes... as long as they aren't canti's.)