I just came across this thread. Not sure if the original poster is still monitoring the thread.... I have been 'off-line' this summer moving from Hawaii to Colorado. Just getting back in the swing of things.
The GRCLT has a few options for 3-week ownership, a few options for 5 week ownership, but the majority of ownership options are 13-weeks per year. Your ownership is deeded and you have the same unit each time you occupy, but the weeks are different year-to-year. So, every 4th year, you get Christmas / New Years (for 13-week owners).
Marriott does offer an expensive option enroll weeks purchased after March 2013 in to DC. Expensive. I was quoted 5,000 trust points *plus* taxes *plus* a $5,000 enrollment fee. That option might make sense for some people, but not necessarily everyone.
I have 3 quarters of a 1-bedroom and then 1 quarter of a 3-bedroom. I originally bought in to the property because I wanted to go 2 or 3 times per year but the weeks I would want to occupy would vary. Except for a ski week or two, I have found my favorite times there to be off-season rather than high-season.
I use a 3rd party rental service that I'm happy with. I enrolled my 3-bedroom in DC and that gives me a LOT of excess DC points.
The property itself is in very excellent shape and, IMHO, run by one of the best Marriott management teams in the MVCI/MWC system. If you like to ski Heavenly, you can't beat the location. The property fronts on Lake Tahoe Blvd, but I have never had noise issues when I have stayed on that side. Both of my units face the pool and it is usually nosier, but it closes at 10pm.
If anyone is still curious, feel free to ask.