We have stayed at all three. Which one is best depends upon many factors such as the ages of the people going, personal taste in themes, if swimming is important, budget and availability, whether or not you want to use Disney transportation to other resorts and more. You mention both CR and BLT. Do you prefer
DVC type accommodations or hotel style? How many people and what room categories are you considering in each of the resorts? A studio in BLT may be technically able to accommodate 4 people, but I wouldn’t stay in one with more than three (2 adults and 1 child). The two of us felt cramped. A one bedroom, however, is spacious and beautiful. At CR all rooms have two queen beds and a daybed and are quite spacious, but only have one bathroom and no kitchen/ kitchenette.
GF likewise has large comfortable rooms, usually with 2 queens and a daybed. VGF are very comfortable spaces as well, with more spacious studios than those at BLT. The proposed walkway to the MK will be a welcome addition when completed, but the walkway is shorter at BLT and already present.
pools at the BLT and CR are both available to BLT guests. However the pools at GF are nicer, iMO. CR guests have access to the pools at CR only, which are fine but relatively unthemed and simple.
all three resorts are very nice and convenient to the. M K in particular,so all are good choices with small children.
i would be very happy with a good rate at the GF,FWIW.
good luck!