Having driven several large Jet Boats I must say that I am still unconvinced .
Low speed handling is like Guinness ( an acquired taste ! ) The fancy tricks (Sideways waltzing and stopping in own lenght from 40 knots )that the salesmen show you will rarely if ever be needed in real life and you lose 30% of your engine power output through the jets .
Their only real advantage is that you have no prop to foul if operating in rocky or dodgy areas ( Which I often do in my real job )
We have had a few over here on trial or demo recently . One enthusiastic sales man ignored my advice to take it easy around the harbour with the Jet RIB (I was worried about wash etc ) .
This Chappie opened her up in the middle of Hodson Bay Harbour in about 2 meters of water and promptly hoovered a half ton of harbour mud through his intakes .
Result ........ Boat stops !!! and didn't go for about another hour despite having a Back Flush Feature !