I've seen backspin on the Oscar Model 1 spinner, which used Logitech mouse circuitry.
I haven't seen any backspin on the Happ controllers, and the newer Oscar boards don't have any backspin, either.
One thing you can do to minimize backspin in MAME is to adjust the analog settings for the game where you're seeing backspin. If you up the key speed and lower the sensitivity, you'll generally see less backspin.
Of course, the best solution is to get rid of backspin at the hardware level...
