I was once quite keen on the BJP site (British Journal of Photography) where I met several people with whom I still correspond, years later. The problem there was that the folks running it didn't really seem to spend any time policing it. I was less than enthusiastic about some of the foul-mouthed people that posted there, and nothing was done to make them polite and not abusive, and I mean truly abusive. In the end, I gave up and a fresh site was created by some of us old BJP members. Problem there, really, I think was one of critical mass and diversity. I think that the chat/forum part of the BJP site has now been closed down...
LuLa has one great advantage, as far as I can make out, and that's that it is run by people who know practical photography inside out. Also, it allows threads to develop without too much interference, and they are also allowed to expand beyond the basic premise of their foundation, often leading to humour, more unexpected information and the sense of a living organism.
I've looked at a few other places, but though they also seem to have some good people, there's just something here that's different in a manner that appeals to me. So, unless I get hoofed out, I hope to stay.