The "coasting inhibition" is a "drag" (pun intended by me at least), but you can activate the throttle minimally, just enough to overcome it and it's not a problem. I purchased an inexpensive DD kit like the one you reference just to see what it was like, and it's surprisingly well made IMO. There are individuals on endless sphere who claim 20,000 + miles with similar DD systems. My 48V, 1000w system climbs the hills in my vicinity like a scared goat on steroids, but they're not extreme like in San Francisco.