You got me to look around and see what's left. What I noticed is, of everything out there, this really is top of the heap here.
The knowledge being shared here seems more in-depth, and trustworthy, and people care enough to correct and elaborate. Activity level is higher. Members seem more engaged. And despite the occasional acrimony around here, this forum is pretty fun (some have all the personality of a phone book.) On that acrimony, and the occasional other sorts of annoyance (trolls etc), I spotted many identical posts and topics out there -- some people will just go and poke every eyeball they can find. The fact that other forums don't get in a dither over inappropriateness seems to be partly that they don't seem discerning enough to recognize it or care.
For all the criticism the forum and the AHA may arouse, it is a community, and a rewarding one. Glad I'm here.