Before we found our 66 Aztec C model with it's STEC 60-2, we
considered a 65 C with an Altimatic II that was inoperable. I called
Autopilots Central and discussed this autopilot with Bob Ferguson. He
took plenty of time and explained the problems with the Altimatic II
and didn't simply brush me off. His recommendation was to totally
discount this autopilot, even it was fully functional. He said that
we'd be looking for a replacement just as soon as we had our first
problem with it.

I have a friend with an Altimatic III in his Aztec and he hasn't any
problems, plus it's still serviceable by most shops.

YMMV
Jim Burns