Montessori is really very dependent on the school itself. We looked at 4 different ones, and out of those we looked at, I found 3 to have issues I could not overlook and only one that I liked. My daughter is in a 3-5 year old class at a Montessori and we love it. There is structure where although the children can pick their activities, they have lesson plans set up that the kids can watch or join and a part of the day where the children work on the same activity. But this is definitely specific to this school, and DD loves how her school is run. However, I sat through every single classroom for observation (twice) - the school said each class is driven by the personality of the teacher leading the room and that different children will do better with one vs another. This school was very serious in its role as a Montessori school but with the understanding that it is not one size fits all. None of the other ones I saw was like that nor had the structure this one had, while keeping to its Montessori roots. So - make sure to observe how the classes are run and ask about structure and such.
Private school... Again, very specific to that school community. DS5 is in a private school and thriving. He struggled (with lack of challenge) in a traditional pre-k hence a move to his current school (our district is rigid about age cutoff and he misses the K cutover by one day). We love it because he is having fun - his math group is already covering material that our public school curriculum does not cover until second grade, and they constantly have new things to work on - and for the first time ever, DS found a peer group that he loves being with. And, one of the things we love is the emotional intelliegence classes they provide for all kids and the respect we see the kids have for each other as a result of that emphasis on not just academics but on social and emotional awareness from upper school to pre-k. DD3 runs around in before school and after school with the school kids and the older kids just include her if she shows any interest in their activities. They have mixed age groupings everywhere so there is no "you are just a baby" even to my clearly underage DD. The kids learn from the start that everyone is to be treated with respect. And this is a core philosophy we agree with. So - in many ways, the school tends to reflect the values of the community and administration (and I suspect public schools are the same).
We have not been exposed to our local elementary school due to the fact they won't even allow DS to start yet, and we can not justify having DS struggle with more mind numbing boredom through another pre-k program while waiting to be eligible for public school.
