Have you used an AP that follows a course sent to it from your GPS or from your plotter? If not, are you happy with adjustments that you make yourself from an AP that follows its own compass and ignores the route on your plotter?
I have had both. The old one was a Wagner S50, bulletproof for following its own compass. A knob on the face or on the remote for course changes, but you have to do them manually.
The new is a Raymarine that is capable of following the course from the plotter/GPS. Just wire it in and select "track".
After using the Raymarine for a few years I find I never bother with the "track" feature. It takes its instruction from the GPS, which I have not updated, so takes a while to enter new waypoints and connect them to make a new route. Also, the bigger issue while in "track" mode is automatic correction of cross track error.
You can be happily motoring along the track, accumulating an unknown amount of cross track error, and the AP will reach its preset limit of XTA and apply a 20° correction. Most of the time that is only surprising. Some of the time that will be dangerous.
Say there is a deadhead that you know is there, but, because it is 20° off your course, you don't need to be concerned about it. If you are not attentive to the course correction, you find yourself running into danger before you know it and may have little time to disengage the AP and get away from the danger. Or another boat, or, or,.....