Yeah as a 58 year old my cruising speed on a regular bike is around 12, 10 on a gravel path, so 20 MPH seems plenty fast for me, I wasn't aware of the cutting out issue thanks for that.
MHS:  I'm a newbie at this as well so I'll defer to the experts here.  But this much I can tell you from what I've learned.    A mid drive offers more torque and will be much better at climbing hills than a hub drive.    As I said that's the challenge for me, getting 240 pounds of me up steep hills.  I was told a 350W motor would probably work but I'm going to get at least 500W if I can afford it.  I also learned that ebike rider surveys show owners love Haibike above all the others.  I"m firmly committed to buying a quality bike for obvious reasons.  Another issue is bike shops are reluctant to work on a bike they did not sell you,  While I''m with you and will buy from a  brick and mortar so I can try first, my challenge is we will be moving at retirement two states away so this could be problematic for me.
The Haibike SDU Cross 4.0 appears to be a good fit for me anyway, I see it advertised around the country for under $2,000.