I had e-assist on my trike, and wouldn't have been without it. You can still get the same amount of exercise, but get far more miles under your bum for your efforts. Without it, I would have been limited to more local rides, instead of really getting out and about. Added to that, there are some crippling hills where I live, that have even the most avid of cyclists forced to dismount. To be able to tackle those means that you don't have to spend hours route-planning, trying to flatten out rides into a manageable state.