I like a regular throttle. On my ebike I run two throttles, one on the right for acceleration and one on the left mounted backwards for variable regen brake that is twisted forward for brake. It doesn’t sound smart until you try it and it is super natural. I have used thumb and grip shifter throttles for the brake and I much prefer the grip one as even with the super light spring on the electric thumb throttle my finger got tired quick due to the unnatural position it must be in. I’ll be seeing how it is to have a full grip throttle for my brake in a week or so.