I have commented on a number London superselctive schools including QEB, HBS, Tiffins, SPGS and "comprehensive" school such as DAO.
Surely one can easily dismiss any criticism as "sour grapes" - though I simply don't have enough DS/DDs to attend all these schools (sweet or bitter grapes won't know) . I do have first hand experience on the process of attending/passed the 11+ test of some (not all) of the schools mention above. ( - when I say passed, I mean rank high enough to get offer). And I do know acquaintances whose DCs in all of those schools above to give insights.
Lets focus on substance of the criticism. My comments are mainly regarding 2 points:
These schools that achieving top public results is largely attributed by the highly academic selective intake cohorts.
Being top of league tables, these schools are target for a subset of parents desperate to get their children into a very narrow range of schools at any cost. Any cost I meant substantial high exam preparation effort, long school commute time or uprooting family at high cost to move closer to these school even good local option is available, and little consideration of school fit in other aspects. A large population of the prospective parents are the ones who typical indulge/obsess in competitive parenting.
The above 2 points might make the schools sweet grapes for some. But to my point, I tasted a sample, it is really sour and not for me and a lot of other parents.