My experience is that there is a lot of misinformation about jets, and that it is usually spread by those who have had very little real experience with them.
The boats originally in question here were the Whisperjet line built by Ted Hood from 1996 through 2003 and ranged from 33 up to 55 feet. These boats were derived from the Black Watch line of boats that hood also owned and produced. They were a modified Hunt deep V. Sometime around 1999 the company was purchased by Hinckley, more or less to limit their own competition. Soon there after all of the molds for the Whisperjet line were destroyed.
Hinckley and Hunt Yachts are now one company (not Hunt Design). While Hinckley exclusively uses Hamilton Jets, Hunt used Ultradynamics water jets in some of its boats.
I have owned two 34' jet propelled 'downeast' express style boats one with hamilton and one with Ultrajets. Both had proprietary joystick controls for maneuvering.
The jets are most efficient above 25knots and consume an amount of fuel comparable to a prop boat at those speed. It is true that it takes more RPMs for a jet boat to get on plane, BUT...that's also a bit untrue as it takes more RPMs to plane a deep V boat than a boat that is more flat aft.
Jet propelled boats due tend to 'wander' more, especially at lower speeds. This is due to the lack of a keel or rudders. The up side to that argument is that the jets have no underwater running heat to become entangled or damaged should one run aground.
How a jet propelled boat is controlled (either manual or electronic bucket control) can be a source of issue for the owner of these boats. The combination of a bow thruster in conjunction with a single or twin water jet set up can be a very maneuverable craft. I have never driven one, but I would think that a single jet with no thruster, such as the case with the inflatable tender, could prove to be quite difficult to control.
Maintenance is often mentioned as another issue with jets. The truth is that jets are fairly simplistic in design and have very few moving parts to maintain. They are all aluminum for the most part and do require very rigorous maintenance when it comes to replacing zincs. Jets are much more reliable and overall less costly to properly maintain than your typical I/O outdrives.
As I mentioned, we are on our second jet boat, and our next boat will most likely have them as well.