I have a 4 year old ds in a play based preschool. 99.8 percentile. 143 score. Last year he was in montessori and HATED it. Although he was happy at home at school he was "depressed, anxious and aggressive." We had him evaluated and were told a) montessori is a bad fit and b) accelerate him into a 4 year old class even though he was 3 (he missed cut off by 4 weeks).
This year he is in a good play based school who agreed to put him in the older class. He's a very social kid and does seem much, much happier. He is adamant that it is not school, just a "play place." What concerns me is some odd behavior. For example, he can write his name perfectly -- with no assistance -- but at school it looks almost illegible. I realized its because he is writing his name at school with his right hand -- but he's left handed. Also, his art work at school looks like scribbles. Maybe because he's never really been into drawing but still ... It's where he was two years ago.
I should note that he has never been "pushed" academically so it's not like he's rebelling against something. Also, he soaks up learning at home and thrives on it but at school he just doesn't seem to engage and doesn't want to do the activities, all of which appear to be fun...maybe not cognitively stimulating...but fun. He is happy and he socializes well, but why would he "work" so far below where he naturally is?