from my experience, the lack of sensor for sensorless brushless system affects mostly during start up from standing still. I am yet to identify any hesitation or drivability problem when the car is moving.
So far, I could not feel any difference between sensor and sensorless once the car is on the move. It's almost the same and almost as smooth as one and another.
With regard to the stuttering when braking. I had that too, but this is a common problem with direct drive pan car or F1. After I finetuned the differential, there was no more funny sound. So, it's not BL system related problem.