Well Bruce I guess our experience was different then. Maybe because my former mechanics (since retired) were able to set it up perfectly right after I bought this boat in 2002. They set up the shift linkage, replaced some leaky trim lines and a bearing carrier that caused a leak. After that it has had NO repairs, not one, in over 15 years. All I've done is normal maintenance, chaning gear oil, pulling the drive, bellows changed, impeller done every 3 seasons etc. And this boat has sat in salt water for 6 months each season, for all that time.
I taught myself to do it because I knew they were retiring and bought the 3 OMC tools to make the adjustment perfect. I didn't even have to change the shift cable. At this point for my next boat I would not buy a modern I/O of either make. They are as complex as outboards without any of the advantages of the older I/Os (simple engines, inexpensive parts) and still have all the designed disadvantages of I/Os. My brother has one, I tried to convince him to wait for an outboard boat but he came across a nearly new 2020 Chapparal 21' with the Merc 4.5 200 hp V6. Starts and runs great like a modern car, but anything beyond oil/filter change, fuel filter change and draining the water via the quick drain is not easy at all. In the manual Merc says you should grease the driveshaft splines (they have grease fittings on the coupler) and the steering cable. Well I looked down there, the only way that's happening is if the entire rear cushion is removed and someone hangs upside down to reach down there. I can't imagine what changing the starter or God forbid the steering actuator would be like. I know bigger I/O boats sometimes have better access but the smaller ones do not.