I can tell you this much: it's not these fora...
But all kidding aside... The Sun Bigadmin fora may not be perfect and a lot of people just run in here with far too easy questions that they could investigate themselves. But if you're in a real fix with a problem, there's a whole bunch of people that are willing to help you out.
Since Sun completely pooched the forums organization on sun.com, the Opensolaris forums are fairly lively, and not full of stupid questions.
http://www.opensolaris.org/os/discussions/
Obviously these are not going to cover legacy Solaris topics. Lots of input from active developers.