I attended a Steiner school along with my 3 siblings (now a physiotherapist, a farmer, a textile designer and I"m a wanna be academic) and we all had a fantastic experience, though not without difficulties and knitting a few gnomes (knitting preceded reading by a long way). So here's some positives, bearing in mind that the schools vary widely especially as they are run by a college of teachers rather than one head teacher and democracy is messy:
we had lots of green space and were encouraged to use it and learn about it.
as a small class we had plenty of teacher's attention.
we were not explicitly taught steiner's philosophy but learned about a range of mythical figures etc.
we did learn conventional science and the school now has up to date computers. (parents ideally should feel free to ignore some draconion aspects of steiner, he was fairly dogmatic at times but also into constantly examining your thinking)
we just loved school and their was a real community feel with lots of festivals celebrated, drama, music, art etc.
Some negatives:
I was embarrassed attending brownies and admitting I couldn't read (it did me no harm, I am a literature student, each child should go at their own pace).
I left before gcses as i wanted to experience the wider school world - found it pushy and stifling, fortunately i did ok under pressure.
there were sometimes long disagreements within the school which led to problems not being dealt with quickly.
the tiered fee system meant facitilities were far less than is usual for private schools. (the hereford school is now a government-funded academy - so we'll see how it goes.)
conclusion: i would love to send my daughter to a steiner school, we don't have one near unfortunately. if conventional education is so good why do people complain so much about it ? at least steiner teachers want to be there (i never saw them smoking dope though it was a local rumour). i would always choose a school that celebrates diversity - we had black children who were happy in our school. i wish i could impart steiner values at home but i've forgotten how to knit!
sorry to ramble on