Sterndrive pleasure boats using boat propellers for thrust have been around for over fifty years and for most of that time it has been the favorite choice for families to use for fun on the water. Starting in the 1990’s Yamaha and Seadoo decided to use a different method for boat propulsion, the impeller jet drive attached to small light weight high revving and even sometimes supercharged engines. Jet boats have been around for decades prior to the 1990’s but those boats used heavy automotive engines for power that burned much more gas than a comparable sterndrive boat did at the time and they were not as fast as a boat propeller driven was.
Comparing modern day jet boats and sterndrive boats, jet boats have a slight advantage on take off from a dead start and turning can be much tighter. A jet boat draws much less water than a sterndrive boat because it has nothing below the keel of the hull like the lower unit on a sterndrive boat does which can be over two feet below the keel. Damage to sterndrives and to boat props happens all too often by hitting under water objects with a sterndrive, not a problem on jet drive boats. Pulling tubers and water skiers can be bit of a problem for jet boats because the jet boat stern can be pulled from side to side by the resistance of what they are towing because they have no stability rudder they turn by the force of the jet. Maybe not so much with tube pulling but hard pulling slalom skiers can cause some problems. Fuel economy has been in the past and still is better with boat propeller driven boats. As much as 20% to 40% better in most comparisons.
Bottom line is jet boats have better take offs, turn better and can be operated in shallower water with no worries of hitting something under water like the stern drive boat owners have. Sterndrive boats burn less gas and are usually faster than a similar jet boat. There is no clear better drive system between the two, pros and cons for each so choosing which one to use is a personal choice.