I was in Miami and got to test the Verdao 350 on a Fountain CC (triple). Really great motors! You can hear the supercharger a bit more because of new air intakes, but they're silent and powerful! It has beefier supports as well as a Bravo 1 gearcase. I really liked it; it had a lot more power than the 300!
Several of the boatbuliders had one concern, however; This is a motor from Mercury Racing, and is not a part of the normal Verado line. There's a 2 year warranty instead of 5, and they mean that Mercury know there is a risk of breakdown.
Also; there was a rumour that Honda would launch a new bigger engine, but this new series is delayed.
Suzuki also launched a 250 SS (SuperSport), which is the 300 engine basically, but somewhat detuned (still over 250) and with a shorter leg.
Representatives from Merc also told me that Yamaha are disappointed when it comes to 350 V8 market response. The engine feels sluggish, and one guy told me that the engine only puts out 329hp on the propshaft. Tried this motor on an Intrepid (triples).