My understanding (and I am still learning) is that Montessori truly encourages teh child to learn at their own pace. There are not structured lessons taught by a teacher, instead a Teacher and Assistant will show the children the tools (toys/learning tools) and they will step back to let the child decide what skill the want to focus on.
They are available for the children for guidance/help etc, however.
The tools are simple, solid structures, geometric shapes, puzzles, nesting blocks, orderly etc. Children learn to put away a tool before playing with another, and they can advance with the tools (use them for different things depending on their skill level).
There are so many examples and details and I would recomend picking up a book to explore them all, or visiting a local school to view first hand.
I have not researched Waldorf schools as much, but I was disapointed that they do not encourage reading for children under the age of 7 in general. Some children enjoy learning to read at a young age and I think that it can stifle the child if they are not encouraged to explore the area of knowledge that intriques them.
Still, many parents love the Waldorf schools, and you may find it to be the perfect fit for your child.
I could go on, but I feel like I"m writing a book! LOL