The standard upgraded autopilots for most of the J/160's have been oversized hydraulic units. The electro mechanical just wouldn't hold up.
Ours uses a B&G hydra pilot driving a Hynautic ram. In 14 years, we've only added less than a quarter pint to top off the reservoir tank.

I think if you have a less robust unit for you boat (relatively speaking) you are mor likely to have failures.