Also, is this a "toothed" belt or smooth? Do you keep a spare belt on-board or is the weak link the (reportedly) plastic gears?
The weakest link is the toothed belt and I probably went through 5 - 7 belts before the gears gave out. The gears in later units were larger and slightly more robust.
Sailmonkey is correct about the belt being no fun the change, you have to take the wheel of to do it and I think the newer versions have ball bearings instead of the little wheels fixed on axles that the older version had.
I can recall
one occasion when I changed a belt one handed whilst steering
with a vice grip on the shaft in the middle of the night because I was in a narrow spot between reefs
and shore and did not want to heave too or hand steer for the rest of the night.
It is better not to tighten the belt too much as then it preferentially slips and keeps from tearing the teeth from the belt. I found that one of the problems was people using the wheel as a grab spot when the boat was rolling and overloading the belt.
The design of the wheelpilot
is not bad it is just too lightly built. I found that for casual weekend use it was fine however when I transformed into a full time cruiser it was just not industrial enough for the work load.
About two years ago I helped another cruiser by fixing his hydraulic unit which the service
person had told him was had it and required replacing. It was a beautifully engineered piece of work from another brand of autopilot with the pump, oil
reservoir and cylinder all incorporated into a single
unit. After having fixed it I realized that I had screwed up and should have agreed with the service
person and offered the owner a couple of hundred bucks for it as spares. This good Samaritan crap just does not pay?
If you can afford it I think the hydraulic drive is the way to go.