All boats that my family have owned were mercruiser alpha one drives and they never ever had issues. Every year they would get removed from the boat during winter, and put back on in the spring when the boat went in the water. Never had a failure. Also, when buying a used boat, the warantee is gone out the door from the get go.
I have never owned a VP powered boat, but I can certainly say that my family has put many ocean runs and 7+ hour trips on an underpowered twin engine sea ray, and even pushing them hard on a 7 hour ride was nothing to them. They also got us out of some pretty hairy 15+ foot swells one time(we seriously almost died on the boat).