We are owners at Marriott's Shadow Ridge resort and were just there this past Fall. We have also stayed at the Desert Springs Villas resort 3 years ago. (That's when we purchased Shadow Ridge, during that stay)
All 3 resorts, (Shadow Ridge, Desert Springs Villas, and Desert Springs Villas phase II) are all in Palm Desert, which technically is a different city, but it's all the same 'metropolitan' area.
Desert Springs is the original resort and sold out. I think phase II is also sold out. Shadow Ridge is the newest at just over 3 years old and is building and also still selling.
The Desert Springs resorts are more established and a little more centrally located, but the villas themselves are showing a little age. However there is a lot of plant and grass around. Shadow Ridge is more spartan as a lot of the planted vegetation is not fully developed.
For comparison, the purchase price of Shadow Ridge was less that Desert Springs units when they were selling, if this helps you at all. Don't think of Shadow Ridge as similar to a Marriott Horizons type resort, but also don't think of it as, for example, Marriott's Newport Coast resort. All the Palm Desert resorts would be between those two levels of resorts, and I would rate the Desert Springs villas a little higher than Shadow Ridge since it is more 'established'.
If you're looking to golf then Shadow Ridge might be the better choice. Also since Shadow Ridge is not full yet (Think of it as an SSR resort that is still being developed), it is not crowded at all. I liked the pool at Shadow Ridge better than the pool at Desert Springs.
If you have any specific questions about either resort you can PM me.
I can't address trading
DVC since as Marriott owners we didn't use any of our DVC points for those trips.