That's a cool video. 8) That engine is noisy though... at idle and WOT
I've been looking at that engine for a while. The engine weighs 800lbs plus, and I don't think they've ever released a price on it (is it even for sale?). I'm sure it's expensive though; just think about the difference in price between a new Chevy 2500 with a gasoline engine vs. a diesel duramax. New outboards are already confusingly expensive.
But- it'd probably last a lot longer and get marginally better fuel mileage like a diesel engine. I just don't know if I'm ever going to get the 4000hrs of use out of the new 4S technology on my boat before my boat rots around it. There might be a market for these engines on the commercial side of boating, but it would be a hard sell to the recreational guys. I think I'll pass.