I've stayed at all 3 and am an owner of DSV2. I don't think that you can go wrong with any of the 3.
If you are staying at the end of Feb. you might run into spring break and the resulting commotion. Early Feb may be "safer".
All 3 of those Marriott timeshares have adult/quiet pools. Sometimes noisy people/kids will show up which may necessitate a call to security. Advice: don't use the pool phone to call security. Use your cell. It will be less obvious.....
DSV2 is split into 2 areas: the main area and Jasmine court. If you want a location that is a bit more secluded and quiet, ask for Jasmine. You can still use the rest of the facility and there is free shuttle service.
At both DSV1 and 2, they share the same activity center, "The Shade". This is used by adults and kids.
The main pool complex at DSV2 is called the Palmeras pool. I think that there are actually 3 or 4 pools there. If you look on maps.google.com you can see what I mean. They also have a cantina for beverages and food.
A recommendation: rent at least a 1 br unit and NOT a guest suite. The guest suite is basically a hotel type room - - small. DSV1 was the first built and the units are the largest of the 3. DSV2 was built next and the units are a little smaller. Shadow Ridge was built 3rd and the units are smaller. Shadow Ridge Enclaves, is still under construction (a potential factor for you). At the Enclaves it is possible to either get the smaller 1 BR or the larger 1 br. Be aware. All of the 1 BR and 2 BR units come with a full kitchen and a washer and dryer (which really makes it easy to pack for a week's vacation).
My personal impression is that Shadow Ridge tends to have a slightly younger crowd and more families. DSV1 tends to have longer-term timeshare owners and might be a slightly older crowd. DSV2 is in the middle.
BTW, if you stay at DSV1, you can use the JW Marriott (hotel) Spa and tennis courts for free during the week. We checked them out and they are nice. But we aren't "Spa people" I guess.