I live very near the bottom of the park (towards the top of Forest Hill Road + Honor Oak) and can say that I find it a lovely, peaceful and calm place to be. The neighbors are friendly and most people I meet are very polite. My only reservation about the whole SE22 thing is the slight inconvenience of the transport links. As long as your a patient type of person who doesn't mind a bit of a commute (and can hack it when your friends and colleagues boast about their uber-speedy journey times), you'll reap the benefits. There's loads of great pubs and foody places in the area and, of course, loads of green space. Perfect for summer. Plus you can park without needing a permit (mostly!).
