All schools are different. Just as there are good and bad state comprehensives, there are good and bad Steiners.
My advice is to go and look at the young adults the school sends out into the world - what are they like? Unless you visit and see for yourself all you will have is rumours.
At our daughter's school, those leaving at the age of 17 do themselves, their school and their families credit. They are polite, informed, well-mannered, keen learners, confident, and able to hold a conversation that doesn't consist of grunts (a rare thing in teenagers!). The school's ethos is about encouraging a love of learning and that really shows through when the pupils move on to study A-levels, and then degrees. If you google "Steiner alumni" you will see some of the jobs that Steiner pupils have gone on to do - there's quite a few arts-oriented types, but also some surprising ones, such as the ex-CEO of American Express, some physicists, engineers and the lady who helped develop modern computer programming.
To answer some of the myths, black crayons and paint are allowed, dolls do have faces and children are allowed to read if they want to, it's just not taught at the school. I don't know any of the parents at DD's school who follow anthroposophy, we just like the school and it's ethos. I like that the school never closes, regardless of the weather (but they do get to go sledging if it snows). I like that the children are allowed to climb trees and learn risk-management through doing stuff and being shown how to do it safely by adults. I like the mutual respect between pupils and teachers.
There is a bullying and SEN policy in place, though the school recognises because of staffing numbers they can only take a small number of SEN pupils at any one time.
As for the gnomes, it's the name Steiner gave to earth spirits (being German). These earth spirits are either helpful or unhelpful. It's no different to those people who believe in gods, angels, fairies, land wights or Santa Claus. Some believe, some don't. It's not a big thing but does look very cute when the children prepare a "gnome garden" at the winter fete
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I'm definitely not a lentil weaver (unless the lentils are being weaved into lentil soup, which is yummy), though obviously there are probably larger numbers of lentil-weavers amongst Steiner parents as they are attracted by the alternative nature of the Steiner education. There are also lots of normal parents (like me!) too.