Hard as ever to say which school is 'best', except to re-inforce what others have said...at primary level you won't find a 'bad' one in the great scheme of things. Secondary education much more debatable IMO....one could not say with conviction that Marple Hall represents the top flight of state secondary schools compared to the likes of Poyonton, for instance....and its Ofsted [whatever your views on Ofsted] reflects that. Stockport suffers to a degree in that its policy of separate education to 16, then 16 to 18 elsewhere, weakens the pool of really good teachers in the secondary schools, since really good secondary teachers want to work [not all!] in an environment where they can teach classes right up to A-level, to stretch their abilities....teaching just til 16 isn't quite the same....so experienced teacher friends tell me.
Hence [in part!] the steady flow of buses in the morning to Stockport Grammar, Cheadle, Hulme Hall, MGS.....