We have stayed at all WDW DVCs except BLT, (which will hopefully happen next year). Can honestly say that I don't have a favorite. I'd be happy to stay at any of them, and typically choose a resort based on what kind of trip we are doing. We are not people who would be disappointed and have a ruined vacation if we didn't get our first choice in a resort. Because of that we bought SSR, (cheapest at the time with later expiration date), where we'd be happy to stay anytime, but try out other places at 7m if we want to go elsewhere.
If I HAD to pick a fav, it would be AKV. Being a vet, I love watching the animals day and night. The colors of the room are very soothing to me, and I LOVE the master baths at Kidani in the 1+bds. The living rooms are also huge and feel SO much more spacious than any others besides OKW. The location isn't ideal to make quick trips to the park, but we deal with that if we are staying there.
Second fav would be BWV which looks to be a popular one. I love the location, and the rooms are comfortable with great views. BCV has a great locale as well, but I don't like the longish walk to SAB, and the rooms are smaller with boring views.
I'd be happy to stay in any of the DVCs without complaint though. I have yet to see a DVC I didn't like. If you feel like you want to be able to stay at a single place most of the time, buy there. If you want to move around like we do, buy where it's the best deal.