We have stayed in the BC and BCV.
The sleeping arrangements will be the most important difference. The studio Villa has a QN bed and a Fullsize Sleeper Sofa. The BC room will have 2 QNs.
The Villa Studio will have a small kitchenette with Micro, Coffee, Toaster, Fridge, and wet bar.
The BC will have a Fridge.
They are both well maintained. The Villas are connected to the main Hotel via covered walkway. It will take approx. 3-8 minutes to get to SAB from the Villas. It could take just as long from the BC from their farthest rooms.
HTH!
The Villas will have Pool View or Woods View/Obstructed Epcot or Main Entrance. You will not see any part of Crescent Lake from the Villas. They are all considered Preferred View by CRO but that is in the eye of the beholder.
I think you can pay extra to guarantee a preferred view at the BC.