A little late to the thread, but as a relatively non-mechanical person who likes boats I think all the advice above is right on.
I had an I/o and loved the feel of the boat and I'm sure it was a would have been as reliable as any engine if maintained properly. However, it was too darn confusing for me to stay current on the maintenance so I let a lot of stuff get run down. For that reason, I'm sticking with outboards in the future.