In-laws have Mariott. They like it. They've traded and gone different places in the retirement years.
I doubt they'll sell it until they can't travel at all anymore. Being he's an ex-Probate attorney, maybe he's drawn up plans to leave it to the kids.
Dad has a "traditional" timeshare in Steamboat Springs but it works for him because it's for a particular "mission", kinda like buying the right airplane... he spends a week long vacation skiing up there every year.
He bought into a VERY nice place and it has "space available" cheap hotel-style rates for owners in the off-season. We've stayed up there in the summer, very reasonably.
The bartender and regular guitar player know dad and we had a ball chatting with them. Steamboat's a great town.
So I'd say a timeshare is a great way to be able to "own" a piece of something nicer than you'd normally buy outright, if you have a specific need to go to that place every year. If not, rent.
Plenty of folks rent out whole homes/cabins around here via companies or often via their own websites for extra cash, up in the mountains 'round here. Or use 'em as trade bait for house swapping.