In 2011 when my 12 year old Autohelm (Raymarine) core computer went belly up they offered me a new current model replacement for 50% of list, a great deal and all my old seatalk instruments worked. I also purchased a new auto pilot head and put the old ST50 head in the nav station and was very satisfied with the deal Raymarine offered.

On the other hand, Garmin only offered me $200.00 off on a replacement for my 8 year old chart plotter.

Then again, all things change so your milage may vary. For me, Raymarine became the brand of choice for auto and sailing instruments.