@waternutt, so far I think that you've gotten really good input on your query. The only thing that was a surprise to me was the comment on insurance being more expensive if you have less experience; I've never encountered that. When I bought my new 2015 AR240, I had no boating history in the US, and I pay $461 per year with really good coverage that includes US, Canada, and Bahamas.
One aspect that has not been discussed regarding buying used is if the previous owner was a knowledgeable owner and loved their boat, you may come across a gem like
@Betik did.
But, I really need to warn you, based on my short experience in the world of Yamaha jet boats, too many dealers and owners do not know/care enough about how to properly care for and maintain a Yamaha jet boat, primarily because they do not belong to jetboaters.net. You might think that I was trying to be a little funny with the jetboaters.net part, but I'm not.
I put my boat up for sale for a couple weeks earlier this year, and one of the guys who came to look at the boat was a current owner of a Yamaha jet boat. When I told him that I pulled my clean-out plugs after every use, he had no idea what I was talking about. Some people buy a used boat, use it and don't take care of it for a couple of years, then sell it before it costs them money to maintain properly, and then they move on to the next used one. You see the same scenario with respect to luxury cars and SUVs.
@MattFX4's scenario is a good one in that his boat still has warranty, but you need to consider the fact that having warranty on a poorly maintained boat does not magically transport you, your family and your boat to a safe place when your boat unexpectedly fails you out in open water.
I have other reasons, but prefer not to share all of them because my post is getting long, but my perspective is that you want to do all that you can to ensure that your family's introduction to boating is a positive one that will create the foundation for years of great family time.
Buy new, unless you come across one that is owned by someone with a reputation for taking care of their boat. Buying a used one from a dealership is like rolling the dice on a dump-and-run scenario.
Good luck brother.