I went ahead and got one, and installed it. Installation was uneventful (despite minimal instructions) and I got it wired up and took it for a test spin today. I don't really have anything to compare it to except for my limited experience riding my wife's Cannodale/Bosch ebike. The pedal assist seems very natural.

I'm happy to test things if anyone has a suggestion. I just really don't have a good reference point. My goal was to have something that would assist going up hills mainly, rather than something that would make me ride a lot faster. I did put the throttle on, and that gives it a real kick. I climbed some hills, and the motor stayed cool to the touch.

It isn't silent, but the sound is unobtrusive (unlike a Specialized Creo I test-rode a few weeks ago, which had kind of a high-pitched whine).

I think I did a poor job getting an appropriate battery. It is so big it was a real struggle to fit it into the triangle of the frame, and it is too big to hang below. The battery weighs over 9 lbs. (I got it off the vendor's website, but it isn't the Cyc official battery).