It's just like any other boat or PWC. Engines fail eventually. The difference is... if you can't do your own work... it will cost you +$7k for a shop to install a new powerhead.
The "normal" mode of failure is just like with the smaller engines.... a melted piston. It's easy to hone, and replace one piston. (not a big deal)
The second way they fail is that the oil pump gear is made out of plastic... and if you overheat the engine... the pump shaft gets tight, and will strip the gear. Needless to say, if the pump stops, you don't have any oil. If you do a rebuild... just replace the gear. THe new style gear is MUCH stronger.
Then finally... yes... you can have a rod let go. It happens, but it's not common. With that said... my engine had a big hole, and it threw a rod. BUT... when I took it apart... the busted rod had a bolt missing. AND... I couldn't find it anywhere. (one was gone, and one was busted in half) So... what happened was... one bolt backed out, and without that support... the rod cap busted, and the crank pushed the rod out the side.
But... like anything... holes can be welded... and sleeves can be replaced.
FYI... I have about $1500 ~ $1600 into my rebuild.