My son attended K-2 at Shaker Lane which is a fine school. I wish the Kindergarten was full day, but it was a good program nonetheless. The teachers are knowledgeable and my son was part of a new program to keep the same teacher 2 years in a row, which I think got his class off to a faster start the second year since the students were well acclimated with each other and the teacher.
ShakerLane is small quality public school. After sending my children to private pre-school in Lexington MA (LEAP school) both children attended K-2 at ShakerLane. The teacher we're excellent and class sizes reasonably small. They also had a number of teacher helpers including parents. I helped out a number of times and greatly enjoyed working with the cheerful and eager to learn children.