Hi there. I think I can help here. We ran out of points and had the same question for a trip at Thanksgiving. I looked into the discount, which I believe was about 30%. Then I looked into rental. The studio room I priced at OKW required approx 75 points for our trip, 6 nights. I paid $10 a point to rent. That comes out to $125 nightly which was much cheaper than the 30% off, which was about $195 a night BEFORE taxes, which I figure would add at least another $20 each night.
We saved money and our rental experience was great. It's easy when you are a member, you just rent from another member. Of course it matters when you travel and what the point totals are, but I am guessing that renting will always save you SOME money.
Hope this helps!