I'm gonna be the guy - not a TUG regular, but love the info. - that says this whole topic and mega thread is pretty "off topic", in that the speculation and reactions to speculation is rampant, with essentially no Facts. It has been a good learning experience for me, though, as I knew next to nothing about the MVC stuff, however, all the speculation and rumors tend to make it more confusing not less, as none of this really tells us exactly how it all will work. As I have remarked earlier, writing this up on the Marriott side will be a very tough slog - trying to make it comprehensible to the "common" owner...and presumably trying to make it enticing to participate in?
Having been to an owner's presentation at WKORVN last summer, then one in Cabo in January, and a relative having gone to one a couple of weeks ago in Palm Springs, I can attest to how all over the map these "rumors" and speculation have been in the sales presentations. We saw an early conversion chart in Cabo in January, but I don't think it was anything more than sales speculation to try and sell from and didn't even match most things folks here are reporting. The relative who went to a presentation in Palm Springs more recently just said what others have been saying - as a Vistana Flex Owner you won't be able to use any of it unless you buy "more" NOW! But here we are, 42 pages into this thread, and I'd say there's been more "off topic" than on. My 2c.
What I DO know is that while I haven't spent hours on the computer searching, EVERY TIME I do search for inventory for trips in planning I either get the system error, or no results, with the "odd" availability at times and places I am NOT that interested in! So this system issue is the bigger factor for right now, IMO.