Unless one has had trouble with an autopilot, it is likely that everyone will support the one they have. I will not depart from that.
I have a Raymarine ST6001 which was on the boat when I bought it.
If I have the opportunity to replace it with no limit on expense, I would replace it with another exactly the same. It is a extraordinary piece of kit on which I would (and have) stake my life. There is no better recommendation.
I have several friends who have the same AP and all agree with me completely.
And no, I have no shares or financial interest in Raymarine
Mine is on a Morgan 44 CC