My first boat was a I/O volvo Penta AQ145B, on a Invader V171.
We started wakeboarding on this boat with a good wake for beginners.

I can't spit on I/O, they do what you want and are drivable on reverse. They got good top end speed, good drivability (not as good as DD-VD), cheaper and easier to find.
The thing that is really missing on that boats is the plateform at water level.

But for wakeboarding/skating/surfing, I will never go back to an I/O.

What I can say about DD VS V-drive :
- Better room, sunbath up of the engine, better Wake size/shape, better surfing ability etc. for the V-drive
- Better drivability at idle and low speed, better acceleration, better for skying, cheaper boats for Direct-drive