SVN and SPG are important...
I'm pretty nervous about the spin-off. We are four star elite and own at WKORV, WKORVN, and WDWV. But unlike, apparently, a lot of people, my decision to buy into SVO had everything to do with the ability to use the ownership at any of the other SVO properties (and future properties) as well as to convert to SPG points and access the hotel network. I first bought into WKORV more than a decade ago and have stayed there maybe three or four times. We never wanted or intended to go back to the same resort year after year. It was the flexibility of the program that sold me. (Although the conversion to SPG points isn't a GREAT deal, it's sufficient to get decent value out of the points in those years where we choose to exchange for them.)
But now that Starwood and SVO (to be Vistana, again) will be separate companies, it seems inevitable that SVO/Vistana will have to "buy" SPG points from the hotel company when owners trade for them. The hotel company will have an interest in maximizing revenue and increasing the cost after the initial terms expire. It seems almost inevitable that the option to trade for hotel points will either go away at some point, or be significantly devalued. And for us, that guts a big part of the value of ownership.
We'll probably be fine on the SVN trades – by whatever name they end up being known – unless the new company sells out or sells resorts off piecemeal, in which case all bets are off.
There was earlier discussion in this thread about the name of the new company, and personally I don't think it's that important. Clearly, for a variety of possible reasons I can think of, Starwood doesn't think they should share their corporate name with the new company, and although the value of the Vistana brand is not huge, it's probably better than choosing some new, made-up name that would start out with zero brand recognition.
The real value is in the resort branding – particularly Westin – and another key reason I chose SVN was because I felt the resorts would be operated and maintained to the Westin standard, because to do otherwise would tarnish their valuable brand. I still think that. Timeshares used to have a lousy reputation, and one of the many reasons was that many were poorly operated and maintained. I felt, and feel, that putting a well-respected name on the property provides a lot of security to owners that their investments will be well kept and renovated when appropriate. Once the initial term of the agreement between the two companies expires, will it still be in Starwood's interest to share their brand with Vistana? That's a scary question too.