Pros
The Head of School at my location was fabulous, as was the Asst HOS she hired. The other teachers were equally wonderful, as was every Montessorian I encountered, from the remote on-boarding experience to visiting classroom consultants.
Cons
Unfortunately, the corporate structure is more appropriate for childcare than school and undermines the Montessori goals. As a results, the Montessori-trained teachers grow frustrated and move on to a more authentic environment. In my experience, the corporate solution to this problem is to hire untrained teachers and train them in-house. I was informed that the teacher I replaced was found in the bathroom crying more than once, and I can understand why. There was little corporate interest in resolving issues that could not be blamed on the teacher. There is a lot of lip-service to things like cultural inclusion, which in practice simply means "we'll provide babysitting for all holidays, including Christmas, Easter, and all national days of recognition."