I suspect the Kawasaki Ultra 250 is right in there. It is a supercharged motor pushing 250HP, in a pretty big hull. I haven't ridden one, but I KNOW they are a ton faster than my 15F, and the 15F is no slouch.
I have LONG been a fan of Yamaha and Kawasaki small engines, and wouldn't hesitate to own either (whether on a PWC, motorcycle, or just about any other application). The primary reason I went Kawasaki over Yamaha was seat configuration and price. To me the reliability is a functional tie between the two.
Sea-Doo engines tend not to last. I don't know what specifically goes bad, because what I usually hear is, "it blew up." I would guess a manifold, and resulting catastrophic damage before it slows down, but I suppose people could be cracking the blocks. The motorcycle companies are pretty good at this high-revving engine thing.
Nothing "comes" with a trailer, but it is easy to get one included. When I bought my Kawi a few weeks ago I got a discount on the boat, a free Triton trailer (which I like a lot), a huge discount on the extended warranty, and a few other freebies (towards accessories).
As for max performance starts, remember, that doing that a whole lot is a good way to cook the engine. Besides, when you are out riding, maintaining a good speed is a LOT more fun than coming down from a plane and starting over.
I am not surprised the Yamaha is a little quicker than the Kawi, based on displacement, but you should ride a NON-supercharged and see what you think, then find out what the maintenence differences are for the supercharged. I personally don't like turbo- and superchargers, but that is left over bias from the '80s when they all sucked.
No clue on the HP figures for the Yamaha, but I can tell you I wouldn't store a jet ski in the water without a ride-on dock or a lift, and even then I would prefer to pull it out of the water for the non-riding months.
Even in fresh water, you can't really maintain a boat properly in the water, it needs to come out. Also, you should be winterizing, and storing properly for the offseason.
Displacement is a very generous 1.8 liters, and its power is boosted by a gear-driven supercharger and an intercooler. Unlike the previous M1 engines, which peaked at a screaming 10,000 rpm, this new motor tops out at a relaxed 7500 rpm. The engine makes 211 horsepower, which looks bad on the spec chart in a class that includes the 250-hp Kawasaki Ultra 250X and the 255-hp Sea-Doo RXT-X, but there’s more to performance than pure horsepower. With about 15 gallons of fuel on board, I clocked the SHO at 67.4 mph on GPS, and zoomed from zero-to-30 in 2.02 seconds. This boat will hang right in there with the Ultra and RXT-X.