Pontoon vs. boat, even a deck boat, is such an apples to orange comparison that I think anyone who has been in each probably can decide what they prefer with just a few minutes of thought. Going back to the original question (and thank you for posting a boating thread in January, much appreciated!
) I think the question is more like this:
Do I want a 20' pontoon or 20' deck boat?
If the answer to the above is deck boat, then:
Do I want a 20' I/O, jet, or inboard?
I don't agree with much that has been posted about jets. Yes, they burn more gas, yes, they take time to get accustomed to maneuvering. But as mentioned in talking about the Tige inboard, inboards are difficult to maneuver, IMO more difficult than jets, yet those of us that own them figure it out and become adept. Of course with any type of boat there is a group that won't become adept and instead are a hazard. On fuel burn, we are people with the ability to boat on Winni for 1/3 of the year, and most of us put 50-80 hours on a boat in a season. So a jet burns more gas, just not a big factor overall IMO, maybe an extra $250 in fuel over a season.
My take - with the 20' limit I'd go I/O deck boat. If you could go larger I'd still consider a twin jet, they are different but worth a test drive to feel it.