I never considered Montessori, either, but I know people who have had really good experiences with the schools, so I wouldn't tell someone not to send their child to a Montessori school.
I had an aunt who was a waldorf handwork teacher, so that was my first, indirect exposure. When I was 13 I started in a waldorf 8th grade in the middle of the year and continued through the middle of 10th grade. It was far from perfect, but it beat out all 13 of the public schools I had attended in my eclectic educational life. It was the first school I encountered where the teaching matched up with the way my mind works: I tend to think in a net, rather than in a line, seeing connections and patterns and gradually building a picture. Waldorf education works the same way.
In a few years I was a mother, so after trying one other school, I put my daughter into the same waldorf school I had attended (my brother and sister also went there, for more years than I did) and she stayed for 10 years, through the end of 7th grade. After a brief try at public school (she didn't like it) we homeschooled for a bit and then she went to the Toronto Waldorf School for her last 3 years of high school.
Now my grandchildren are at a truly lovely waldorf school and they love it.
Besides the general teaching approach, I like the outdoor play, the physical movement, the handwork, the breadth and depth of the curriculum, the way drama is incorporated into every grade, the music curriculum, the amazing exposure to literature, the artistic activity...
My daughter, among other things, is an engineer. I like the way that waldorf provided her with the ability to be artistic and logical.