My 2 1/2 year old child started at Kaye Kare in July and seems to really like it. Compared to other places in the area, its a great deal ($225/week). They do a good job. She's learning, while also having a lot of fun. We were actually on the wait list at another preschool, but decided to keep our kid at Kaye Kare since there is a significant price difference and we didn't feel that the quality difference was all that much.
Basically, compared to other preschools in Arlington and Falls Church, Kaye Kare is a great deal. I just don't think the other places were all that much better, if better at all, and they are a lot more expensive (e.g. Ballston Children's Center is a lot more money, but I really didn't like them and many of our neighbors didn't like them either).