I have stayed at both and like both very much!
At one time, I owned at Mountainside Villas. It has a queen in the master bedroom and two twins in the second bedroom. There is a sleep sofa in the upstairs loft area, which is where the bedrooms are located (upstairs). The other sleep sofa is downstairs in the living area. They are very well-maintained. They are very large and have a wonderful jacuzzi room with a dry sauna and shower/toilet with an additional full bath upstairs between the two bedrooms. The kitchen is nice and big with an eat-at bar and a nice large dining room that seats 8. There is a balcony off the loft area and a patio/deck off the living/dining area. There is no washer and dryer in the unit. There are washers and dryers at the Welcome Center for the Mountainside Villas where you will check-in. Unlike Woodstone, Mountainside Villas are up on the mountain and you will have to drive to get to everything. There is an indoor pool/recreation complex nearby, but it would be a bit of a hike to get to. We also enjoyed our stay in a Woodstone unit, which had a partial kitchen. The partial kitchen never presented a problem for cooking. It had a microwave, gas grill, two-burner counter stove, electric skillet and a toaster oven. We are a family of four and were able to cook all our meals in for the week. We also used our car to get everywhere when we stayed at Woodstone. We prefer Mountainside Villas probably just a bit more because they are so large and everyone can spread out into the different areas, it has the nice jacuzzi room with the dry sauna and we enjoy using the Jenn Aire grill. The only drawback is not having a washer and dryer in the unit.