Experience with Da Vinci Center for Gifted Children

We are considering sending our current 3rd grade boy and preschooler to Da Vinci Center for Gifted Children. Our third grader seems to be bored from school and not challenged enough. He goes to a "rigorous" private school right now where homework is assigned every night (not weekends). He doesn't have a learning disability. The very few comments nor reviews online suggest that the school may be a positive experience. But we'd like to hear more to get a better feel of the curriculum and school. We are concerned that there are only two class sessions a day and whether or not there is sufficient amount of time devoted to learning. Our son is not the type of child who wants to do work and we are concerned that he will be playing quite a bit without homework and studying for tests. Any feedback welcome! Thanks. Nancy