Actually there's a post about 12-15 items down the list covering this very topic.
DVC busy vs. Park's not as busy: Basically end of Sept - 1st week of Nov is busy for Food & Wine Festival. 1st 2 weeks of December are busy because of low points.
Basically (from what I can tell) Disney lowers points during "slow" times of the year to encourage DVCers (who can make their points go further by going on off times). If you want slow DVC time and slow Park time - look to the middle ground (the Choice and Dream seasons).
Chris