I know some people love Montessori but since you asked for opinions...
It seems very restrictive to me. Perhaps not compared to other school formats, but compared to how home education can be.
For example, the materials are only to be used in a certain way. As I understand it, a child cannot take the stacking cups over to the pouring area and use them as boats, or wear them as hats, or remove the laces from the lacing station to tie the stacking cups together to make a robot.
There are defined tasks. It's true that the child is allowed to choose from among them, but she can't define her own goals. In common with any curriculum, the Montessori approach assumes that someone else understands what the child ought to be learning at a particular age, and what materials she needs to achieve this, better than the child herself does.
Many of the tasks are to be carried out individually, even though children often have the urge to collaborate.
I guess Montessori is child-led in the sense that the child is presented with a fixed number of different paths and allowed to choose one of those paths and go down it at her own pace. It's better than telling her which path to take and how fast she must go. But I would rather set my child free in the world to forge her own path, or even just sit and eat her sandwiches and watch the clouds for awhile if she isn't ready to go anywhere yet.