The question is not "is this a good school?" but "is this a good school for my child?"
I moved DD from an outstanding Ofsted school to a satisfactory one.
We did it mid year as well and I know the head of her old school was a bit cheesed off. However DD is thriving at her new school. She is a bit of an oddball, doesn't like lots of noise, very bright so at her previous school she was correcting the teachers, likes to be alone a lot, hates group work...so although her old school was ok at dealing with her, as it got towards SATs she sort of got left out as they concentrated on the tests, which was fine for most of the kids but not for DD. So now she is in a school which allows her more freedom to work on her own, or do different things or delve deeper into her pet subjects.
We looked for: attitude of the head, children's playing at lunchtime, interaction with the older children, were the toilets clean? Did people greet you and the head as you went through the school? If you spoke to a child how enthusiastic were they (very enthusiastic in this case) - ask the children the best and worse things about the school, that's always an eye opener. Is there an emphasis on sports? Pastoral care? Children's emotional development? Academic? Results driven?
If you ask the head about bullying policies, do you get fobbed off? One head said "we don't have that kind of thing here" which instantly got the school crossed off my list - unless he's rewritten the human genome, some form of bullying exists in all levels of society, what he meant was, he wouldn't address the issue, a complete no go for me.
How close is the school? We really liked one school but 2 hours a day in a school bus made me reject it.
Do packed lunch children and school meals children eat together? We didn't want DD separated form her friends for silly logistics issues.
What kind of after school activities are there?
How do they deal with those who are a bit behind?
How do they deal with those who are more ahead
Many schools do one or the other but rarely serve both of these groups well. If you have a child in either group, it can become a big issue.
Social and emotional skills - how are these taught/modelled in the school.
Attitudes of other parents as well- if you get to see any (like lurking at the school gate) - I walk with a stick and was openly sneered at by a group of mums when I got out of my car to look round the school. That school got crossed off my list as well.