I installed a cable-brake Wheeltop setup a few weeks ago. I installed it on my groad bike, and I am currently running it as 11 speed. Other than the initial setup being a pain in the ass, it has been flawless. I shift 400-500 times an hour, and use about 20% battery in a 4 hour ride. The Android app, could be a lot more intuitive, but I’ve gotten used to it, and it can do anything you need to do.
I have 2 sets of wheels, and swapping them out is no problem. I need about 30 seconds to adjust the derailleur using the app, and I’m ready to ride. I came from a mixed Ultegra/105 mechanical setup, and the shifting is at least as good, if not better.
So far, durability isn’t a concern. I was washing my bike with the wheel and chain off, and dropped it off the stand. It landed on the carbon rear cage, and bent my hangar to a 45 degree angle. There was no visible damage. After straightening the hangar, shifting is fine. I was somewhat surprised and very relieved.
Future miles might change my mind, but I wouldn’t hesitate to buy another Wheeltop setup.