I've seen the ads - but don't know anyone who is a member.
I saw an article somewhere within the last few weeks that said this organization, or one of their competitors, will let you stay at one of their properties for a few nights, paying a fairly steep nightly tariff, but without paying the large upfront fee. Seems like a reasonable due diligence expense.
Also - what is the ownership structure that you get for $350k? Is something deeded? Is it an LLC interest in all the properties?