I was reading a lotof the old threads about Montessori, because we have a local nursery, plus there was a Steiner playgroup where I used to live... I struggled to get my brain around it, too.
It seems like both philosophies try to treat the children as individuals, expected to learn at their own pace, and not as part of a group experience of learning. In Montessori they focus on academic-type skills, using individual not group teaching exercises. In Steiner, it's all exploration, lateral thinking stuff.
Montessori gets criticised for being too strict, too structured, too much expected in terms of individual self-motivation. Steiner gets criticised for the opposite for being too unstructured, & children not being taught discipline or group dynamics. The mum+Tots group boasted about parents being surprised at their child cooperating at tidying up if the tidying up song was sung WTF? Thought DH and I. Most children will tidy up if it's what the rest of the group is doing, most children like doing what they see their peers doing. Children, esp. age 3+, really like rules and structure -- they like thinking that they understand how things 'should' be. It's nothing to do with the special song!
I think you have to visit both of the local facilities to see which you could imagine your child being happiest in. I would chooose neither though. Steiner esp. is way too hokey for me, but ours is a household of engineer/scientist/statistician types.