I have had two daughters go through the Runkle school. My eldest is in 8th grade and has had a very good experience overall. I do think that they do an excellent job from 5th grade on - the earlier grades could use some differentiation particulaly for the brighter students. The math curruculum has changed for the better in the time we have been there. The middle school environment is very small and can be somewaht 'inbred' and claustrophobic.
My daughter is in 6th grade now and has been in Runkle School since kindergarten. She comes home every day telling me stories about what fun things they did in class today. Runkle has experienced far less social class difficulties (a.k.a. 'popularity') and drugs and alchohal problems than the other Brookline Public Schools. Her teachers are always willing to help her and are kind and smart, too. I would rate Runkle 10 out of 10!