After purchasing 2 weeks from Marriott (MCVI), I bought a Starwood. I totally LOVE their flexibility, ability to use my points in various ways, and if a room is available, I can have it, points or cash or some combination.
I, too, feel that MCVI is slipping with respect to maintenance and upkeep (despite my annual fees going from $800 in 1999 to $1300 this year). The staff are still good, but it seems like the furniture isn't rplaced as often, the rugs aren't as clean, so on and so on.
Add to these concerns the new point stuff. I'll use my Starwwod Amex card from now on.