I sent my son to Montessori for two years before Kindergarten- mornings only. I asked, and was invited to observe for several days before deciding.
I went to two different ones in my area to discover what if any, were the differences between them. I was comfortable and pleased with what I saw at both of them.
Most of the time was spent playing and learning was a byproduct of play. I didn't want my son starting "school" too soon anyway. There was discipline, structure and respect.
Two of the teachers were on the local Republican committee- and I never observed any "agenda" being pushed by the teachers.
My son has happy memories of his time there- as do I.