I own 3 Starwood weeks at voluntary resorts including 2 weeks at SDO (all resales) but have never done any trades because I always thought that SW picked the week that got deposited so the trading power would be poor. However, I've now learned that this is not the case. If this is in fact the case, I'm pretty well convinced that you're actually better off not being in the SVN if you own a voluntary resort and you basically have the best of all worlds.
First, since SW picks the weeks for virtually all deposits to the exchange company (even if they're not supposed to for non SVN deposits), it's much easier for an owner to call up and get a highly sought after week. The only time I've ever had to call right at one year out was to reserve my SDO unit for Super Bowl week. Otherwise, as long as I called within 6-9 months (sometimes less), I've been able to get a peak week because SW deposits the bad weeks! With my Marriott TS, it's almost impossible to get a peak week unless you call 12 mos in advance to the minute.
Second, you can reserve a peak week and have SW deposit that week for you (although it might be akin to WWIII to get them to do it, so it appears).
Third, if you're in the SVN, they charge you a fee (something like $39) to change a reservation but there's no charge to do it if you're not in the SVN. If you reserve a week to rent and it doesn't rent, you can even change it up to the day before check in to a new date, and there's no penalty if you're not in the SVN. I've had reps tell me that it would be a $39 charge to make the change but when they finally see that I'm not in the SVN, they say there's no charge. Most everyone who owns SW timeshares must be in the SVN.
Fourth, you don't have to pay the annual $109 SVN membership fee.
So, net net, I think you're a lot better off not being in the SVN.
Also, all three of the SW weeks I own are the small 1BR's and I've never had a problem renting them for quite a bit more than my M&T, but I always reserve them for one of the highest demand weeks of the year. Carolyn, you might not get $900 for your small 1BR at SDO but you should get at least $700 for it which is well over your M&T. One bad thing about an EOY at SDO (and maybe other SW resorts) is that the M&T is a little higher than if you own EY (i.e. you pay a little more than 50% of the EY fee each year). The large 1BR will rent for more but the M&T on it is also more. The main determinate as to how much rent you can get is the demand for the week, not the size of the 1BR unit, IMHO.
I think you'll be very happy with your purchase at SDO.