I think it would be quite unjust and rude of me to say that I "benefited least" from extra facilities! We all knew how lucky we were. I wanted out because I felt it was wrong.
Have to point out as soon as I got "out" and went to a 6th form state my A'Level predictions from 4 A's went down to 2 C's and a D because I am intrinsically a lazy bugger. Having had 10 yrs as a boarder in a boy free environment wasn't, it turned out, the best idea when at 16 I was put in a situation where I had no parental support, boys wherever I looked and no wish whatsoever to do homework or turn up to lessons but instead a strong desire to gallivant in open spaces and attempt to re-create what I thought I had missed out on by going to a private school. I may point out that I was not the norm for my year and most girls I left at my private school probably would have just ignored the outside world and boys 
End result = yes, it was privileged but I probably don't have the wherewithal in me to be able to string a coherent sentence together without it. It gave me the freedom to see that I was privileged, didn't make me abuse that in the slightest and helped me learn to the best of my ability. I am confident I would not have got the grades I did without it.
On the other hand, the state school showed me just how durable kids without families have to be to get to 6th form. No other child who had made it that far was living independently of their family. This was a highly regarded comp in Guildford so again, not exactly a rough area.
I'm personally glad I live in a Grammar area, as I can see pros and cons to each side, and yes, I do have a social concious. However, no doubt now it will become unfair because if my child is bright enough to get in I'll be punishing the local comp by not letting them benefit from her wisdom, rather than trying to help her get a better education amongst peers at her level?