I have one on my 32'. In calm seas < 3', works great, but never trust it in chop or around boat wakes - won't react quickly enough. A lot of it is because of the shallow draft of our hulls...
Would I spring for a new one? Depends. Wouldn't be on the top of my list, but it's still nice to have. Setting "Zero" is a little less intuitive than you might think (no visual feedback on the unit I have, just lights that blink).
Using any of the manual trim tab controls automatically disables the unit - this is a safety feature.
Side note - When I bought my boat, it had been shipped from the east coast. They miswired that control, when reassembling and it reacted opposite of what it was supposed to do - scary moment. I thought the boat was going to flip :(
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1987 32 Sedan Bridge
Twin 360s, Rebuilt 2006
Modified/Original Electronic Ignition
Raw Water Cooled
Catawba Island, Ohio