I've had nothing but good luck with the SeaStar system on my boat. The system is 11 years old and has not needed one seal in either the head or ram.

As Denny has said, get the biggest helm for the fastest response. If not, make sure you have a small wheel. I do know of folks that have had seal problems but I think it comes down to preventive maintenance. I keep the system coated with a light corrosion resistant spray on all components and change the fluid every couple of years. It should also be noted that the availability for autopilots is pretty much confined to hydraulic units. That may note seem like a concern but I installed one on my 23 a couple of years ago and wonder why I waited so long.

Ordered a SeaStar unit yesterday. Figured I didn't want to deal with it twice if and when I repower. Thanks for all the feed back.