Montessori vs mass teaching

I've sent the boy to a Montessori school and now a typical school where teaching it's done in a mass. Which one do I think is better? I say the former.

Montessori teaching is very individualized, the kids learn at their own pace and have one on one coaching from the teacher. Actually there's no lessons, they typically work on materials. By observing them, the teachers are able to asses each child's learning level.

In a typical classroom setting, the teacher conducts a lesson using one method for all. There's little one on one coaching, and every child do the same work at the same pace.

I find in the latter setting, it's more difficult for the teacher to know exactly where the child's standing is. When n was in Montessori school, the teachers would report to me his exact standing I.e. He knows how to add, read etc. But in this school, there's no such feedback. He's like any other child in the school who's learning his Phonics and counting. I've not received any report from the teacher about his learning stage. She was even surprised when I told her n could read on his own- she claimed he was just memorizing the books they read in school. In other words, she hasn't discovered where N is on his learning ability. I don't blame her, it's the teaching style that they used. Moreover, it doesn't help that the boy keeps things to himself, he doesn't exhibit his knowledge openly. He needs to be pried openly carefully and slowly. Hee.

I kind of miss the Montessori school and I'm worried that this school is limiting his learning. It's dawning on me more each day that I can no longer teach him as liberally as before. That said, n is happier in this school. He enjoys the other non curriculum stuff like the singing during assembly, the gym etc. But.... But....