I've only stayed at two
DVC resorts: WL and BC. I found bus service from WL to be quite good, with fairly quick stops at other resorts before heading to the parks. I found bus service at BC to be pretty frustrating. First of all, the waits seemed to take a long time, and then it seemed to have to stop at every single other EPCOT area resort before heading back to BC from the parks. Very annoying and time consuming. However, you don't need bus transportation to 2 parks from BC. You can take the boat to MGM and walk to EPCOT.