Are you planning on keeping the boat at a dock, or on a trailer? If the former, definitely avoid any I/O. Leaving the outdrive in the water 24/7 will be a maintenance problem.....just a matter of time. That big hole in the transom at/below the waterline is up there in design hierarchy with screen doors in submarines.
IMO I/O's became popular initially because outboard power was limited....200-225hp was the upper limit for a long time. Reliability and longevity were also challenges. I/O's were the best bet for higher power and trailer ability (missing the running gear and rudder of an inboard). Modern outboards are available with much higher power, and have become very reliable (with proper maintenance of course). Expensive, well sure, much like Porsche engines......
