No, there is no bobbing or reaction to pedaling. But on a 25.5mi ride today, I didn't pedal much anyway. The Shockster and the battery mount have stiffened up the frame to a noticeable fashion and mounting the battery down low on the bike helps a good handling bike be even better. It makes a good electric motorbike for the bike paths, it tops out at 32mph and cruises easily at 12 to 20 mph. I used 504w according to my inline wattmeter, so I should have a decent range on motor only since the pack is 20.5ah. BTW, the wattmeter showed I used 5.82ah so, on the flat, I have a theoretical range of about 75 miles without pedaling.
Now I have to find a way to get the cruise control in the Magic Pie to work: the spring in the Golden Motors thumb throttle is waaay too strong to hold onto for so long..... It I sure is fun to ride though!!! Handles like a sportscar, has great acelleration and 30mph is fast enough on the flats for me. The tires felt great and had great traction, plus it coasted forever, but the 10 year-old Cool-Stop pads seem to be a bit hardened and howled/squealed a bit.