Once you excede 250 watt motive power you can't "legally" use it where MTB's are permitted by the so called powers to be. So you might as well go full monty and embrace petrol power:P
Yes, EMTB have their place, on tracks and forestry roads. But try heading bush for a 5 day hunt, all equipment on board, 30km ride in, and two deer on board for the trip out. Even the lowly mudbug, with its minimal suspension, is streets ahead in the comfy arse and carrying department:ORLY:
Attachment 176467
800m in front of this photo is a shaley slope inclinometered at 29 degrees. Bikes putt up there, no running out of puff a third of the way up:omg: