The standard textbook thinking is that Jons are good for Bass Fishermen who work the shorelines, weedbeds and shallows, while the semi-v is better for trout fishermern who troll the deep water.
But from personal experience I can state that it's not a rule written in stone. Plenty of Bass fishermen
prefer semi-Vs and plenty of Trout fishermen use Jonboats. Myself included. That said, the semi-Vs handle
better in windy conditions while Jons are lighter and easier to launch and put away by yourself. Also while
the standard Jon is 44 inches wide, there are now 56-60 inch models designed for Bass fishermen who like to stand and cast. Semi-Vs also cost more than Jons but a 12ft semi-v usually handles up to 3 people while most 12ft Jons are for 2, However the extra wide Jons at 12ft are good for 3 passengers.
A 14ft Jon is another option, they are good for 3 passengers, fairly easy to move around, and handle
better than a 12ft because of the extra length. A 14ft semi-v would give you the most room but I wouldn't want to move it around by myself.