I have used both and prefer the Simrad over trhe ComNav and intend to install one myself and most likely go with the AP35.
Alot of lobster boats are running thier haulers off the transmission.No drive shafts or belts.
I have had the COMNAV 1420 Series in my boat for 4 years now and Iâ€™m happy with it. Itâ€™s no Simrad but it does what I need and its around 1/3 the cost. I was replacing an existing AP and was able to use the previous pump w/o any issues. I think I paid $900 for the entire system minus the pump. Installation was fairly simple and quick thanks to the pump already being in place. I have it interfaced with a Lowrance GPS and it was an easy interface since all that was needed to connect to the NMEA output/input was some speaker wire. Easy to calibrate , has a good range of settings, tracks good and is fast in most sea conditions. I just go it with the fluxgate compass but you can get an optional Heading Rate Stabilizer which supposedly helps in very rough conditions but Iâ€™ve never had the need for it. Unit is simple to operate and if youâ€™re not looking to spend a lot and have a reliable AP w/o all the bells and whistles, COMNAV may be the way to go.
Hope this helps.