I liked Montessori for my daughter (now 9). She went to a school that was preschool through 8th grade, and kids were allowed to progress at their own pace. She's since been diagnosed ADHD, and looking back I can see how montessori gave her some much needed structure and organizational skills.
However, my current experience with my son (4) is, well, meh. The school he's at only goes up through pre-k and it's not a true montessori, though they use many of the same methods and materials. They just don't have the resources or advanced materials to deal with a kid who's more than a year or so ahead.
So I guess my advice would be to ask how far ahead a school would allow your son to go, and if they have the experience and resources to support him.
