Five levels of assistance on the controller - from little assist to a lot, up to 350%.
Level one is probly 50%.
Pedal pressure is often measure in newton-meters of force. But I can't tell you how all of this is measured. The yamaha drive is one of the most powerful, is quiet, smooth, and reliable. Very well spoken of by the industry.
Have you ridden one? Level 5 is amazing - you hardly even have to pedal. I usually ride in 3, sometimes 4, and only 5 for a big hill.
The torque and cadence sensors provide more assist as you pedal harder and faster. It's very seamless and smooth, like having Lance on board pedaling with you.
Well, there is that setting, but I've never been able to tell the difference, or what it does. Supposedly it was for fine-tuning assist, but just not sure why one would need or want to.