My son attended La Jolla Country Day School for a few years. As a CV area resident, he currently attends CV schools. Sometimes I regret pulling him out of LJCDS.
With regards to parental involvement, I give CV schools a slight edge. Many LJCDS parents are busy and have nannies drop/pick up kids. There is little casual encounters among parents except at organized school events. For class size, LJCDS is smaller. I remember my sons K class had about 10 kids and 2 full time degreed teachers. For curriculum and overall enrichment, LJCDS wins hands down.