I bought an ex-Sunsail charter boat and was very happy with what I got for the money
I paid, but knew that it would have cosmetic issues and need some TLC
Then I bought a secondhand private-never-been-chartered sailboat and was very happy with that as well, the premium I paid was worth the nicer interior
The used charter market is pretty big for a limited amount of boat models, so the pricing is as close as you are going to get to a "market value" and the owners (often the charter companies themselves if the previous owner trades up to a new charter boat) are motivated to sell. That is not the case in the private market and many owners place prices on their "babies" that are not realistic. Some private boats are in worse shape through neglect than the charter boats are through heavier use.