To add to the points above, don't look just at final SATs results. Also look at what (to date) appears on the tables as 'CVA' - contextualised value added.
This basically measures the progress children make in that school from the end of KS1 to the end of KS2. 100 means that they make exactly the expected progress.
To give some examples from schools I was looking at when we moved:
- School A: very high final SATS results but CVA significantly lower than 100. Ofsted Outstanding BUT when I visited it was apparent that a good deal of covert selection was going on at entry.
- School B: lower SATs results, CVA significantly higher than 100. Ofsted Good. Very inclusive, approach to 'unusual' children - DS was still selectively mute at the point at which we moved - extremely positive and friendly.
We went with School B and have never regretted it.
Ofsted is now [since the new framework came out, so from beginning of 2012] very interested in achievement AND PROGRESS. So some schools which are used to getting very good results and good / oustanding Ofsteds because of very able intakes are finding themselves being downgraded because they can't show that children of all abilities are making above expected progress.
I work in a school which used to have a satisfactory rating, and has unusually high numbers of SEN children and those from disadvantaged backgrounds. We worked our socks off, looked at everything we did, improved in all sorts of ways, lots of dynamism, lots of energy - and got a Good under the new Ofsted framework [which since all the levels have been changed, might well have been an Oustanding in the old one]. Equally, a school local to where I live was Outstanding, sat back on its laurels, and the Ofsted inspectors came in and downgraded it to Satisfactory ... it is sometimes better to be a pupil in a school which is striving to improve than one which feels that it has 'made it'...