My child attended the Pre-K program at CDS and thrived. The classes are small, the teachers are amazing and the facilities are well-maintained. The Pre-K is self contained and has a small playground, it's own restrooms and easy access to the library. It is not in the main building of the school where the lower and middle school classes are, although the children do interact with older students through a "big buddy" program.
PROS: Well-educated teachers, well researched program
CONS: Very expensive once children get to lower school