Here's what my research indicates are the pros and cons of renting points:
Pros:
1. Huge savings (as much as 70% less than booking direct through Disney)
2. Along the lines of 1, can get a villa at the deluxe level with in-unit washer/dryer, kitcken, etc. for less than a value suite.
3. Two bedroom villas are particularly nice for large families (or families traveling with grandparents, etc.) because you're guaranteed to be in the same unit.
4. Still have access to most of the benefits of staying on-site (e.g., Magical Express, EMH, free parking, bus service, dining plans, etc.).
Cons:
1. Must book early (the most popular places, such as BLT, can quickly book up 11 months out).
2. You're not in control of the reservation in that you can't communicate directly with Disney (although a good broker or cooperative owner should make this a relatively minor downside).
3. If you rent points through a broker, you typically must pay all costs up front, which are nonrefundable (although vacation insurance can mitigate a good amount of this risk).
4. If you rent points directly from an owner, you run the risk of being taken (so doing your homework and dealing with someone you can trust is huge).
5. You won't get daily maid services and towel replenishment unless you pay extra (but some see this as an advantage in that you don't have someone knocking on your door every day to clean your room, i.e., more privacy).
6. You won't be eligible for
free dining (but you're saving so much more than FD, plus you can cook/eat in your villa).