Play is a big chunk of Montessori learning - as opposed to "mainstream" sit-in-desks-shut-up-and-look-at-the-IAWB learning.*
Ah right fair enough then, I know very little about but I do know that my kids are doing just fine in standard education.
In fact, I suspect that many preschool / nurseries nowadays are the way they are due to the influence on Montessori on the mainstream education systems in the last however many years, whether they call themselves Montessori based or not.
There does seem to be just about the same style of education done at our kids' nursery and school as to what people have said on here to what their kids receive at Montessori schools. No idea what came first though.