I know POD's are not on the table here, but will throw in my .02.
When I first got the pod's i was nervous as crap. I still am to a degree, but the performance of the pod's is right up there with I/O's. Maintenance is lower. I know POD's are pricey but (knock on wood), they have been very good to me.
Keep in mind I am running POD's in the shallowest of bays too!
Volvo has done an amazing job technology wise here and I am impressed at the power plant in my boat.
With all that said, would I pay the money to get pod's in a new boat? That would be a tough call. Inboards certainly are a simple design that works well, but I have seen and heard of 2 inboard boats sinking recently due to seals gone bad. You don't have that with POD's.
If you never drove a POD boat, trust me, once you do, you won't want another system!