To me, "reliability" is the first, 2nd, and third qualification for an autopilot.
I like controls that have Left 10 degree, right 10 degree buttons at the control (most but not all do). To avoid a lobster trap while on autopilot, I simply hit left 10 once, wait a few seconds and then hit right 10 once and am back on course. Very hard to mess up.
Be sure to install a "rate compass" or it won't steer well in tough seas. If you want to get fancy consider something like this Airmar (watch the video)
http://www.panbo.com/archives/2009/02/airmar_h2183_compass_best_in_class.html
I've never had an autopilot do particularly well steering to a wind direction instead of compass although they have the capability. If you wind sensor swings at all in a seaway the autopilot computer is challenged.
Simrad has a long history of robust autopilots - not just pleasure but commercial. I've had an AP42 for five years without a moment of trouble. The AP24 control looks old fashioned - but I really don't need fancy graphics for my autopilot. They are now part of Navico. Hopefully this doesn't reduce quality.
Garmin is newer in sailboat autopilots and also has a reputation for reliability. If you had a Garmin chartplotters this would seem worth a hard look.