School me on I/Os

[erebus]

like bobr mentioned check the oil pan, or at least ask about it.
They get really sweaty sitting way down there in the bilge.
Had to replace an oil pan on an I/O silverhawk (basically a 24 Seacraft) and a 23 I/O this year so far (also an aged Tiara but we wont talk about that :-P).
They rust out right around the drain plug.

Take some notes and some pics and come back and ask away.
There are so many variables its hard to tell you what to look for without knowing what you're looking at. Hopefully not a volvo...

I have access to a 23 CC with an I/O (Fuel injected Mercruiser Horizon 350, with a bravo) on Pleasant bay and I think it handles great. Only downside to the IO is you cant really drive it right up on the beach, if that's your thing.
Cant trim it all the way up and skim along on the hull in 10 inches of water like you can with an outboard.
Maybe that doesn't matter, but it is something to consider.