I tried out a rapidwinder that a guy wanted to sell which he'd bought and didn't like, but I couldn't advance any faster than with the regular lever. I'm a "right eyed shooter" and with the M eyepiece being way off to the left end of the body and my head/hand size what it is, I can work the advance lever without taking my eye from the finder. Another thing, I read once where somebody questioned whether the trigger on the rapidwinder/Leicavit could cause injury or damage if the camera were to drop or swing around. I admit the thought wouldn't have occurred to me, but I can see where there could be some merit in that concern.
As to the motors, I've got one of the older type, it was cheap and thankfully one of the quiet, smooth ones. I must've used it all of six times in the 4-5 yrs I've had it. It really just about doubles the size of the camera. The latest motor I've only handled on someone else's camera. I find those rounded grips very uncomfortable, and the motor has one.
All of my gripes are very subjective and personal and many people feel just the opposite. As is usually the case, bottom-line, once again I say "try before you buy".
