In a nutshell, BWV, BCV and VWL all have units similar to each other with the only difference being the decor.
All have apartment size W&D, apartment size kitchen with smaller refrigerator with no ice-maker. All are attached to a hotel with interior hallways In reality a 2-B/R is similar to taking 3-hotel rooms and connecting them. Basically the LR, MB/R and 2nd B/R are all the same size.
OKW is more like a traditional timeshare, or a traditional house arrangement. Outside entrances, Full W&D, full size kitchen, etc. as has already been mentioned. OKW is the one resort totally different from the other 3 resorts at WDW.