Just my view upon this: I find mailing lists (ML) very convenient and I don't follow forums in general except of the "ubuntuforums.org". But MLs have several drawbacks.
One thing that is not that good in MLs are LONG threads as the current one. It's hard to follow sometimes and people tend to post irrelevant stuff on a ML-thread or change the subject of it so a new thread starts when it's not required. In addition, it's not possible to mark ML-threads as SOLVED. The latter is, in my humble opinion, a big drawback. Fora require more energy to maintain but provide means to organize information better. Of course, the LyX-wiki is very good which fulfills most of what the ML doesn't satisfy. That said, I think a ML + Wiki are enough. Without the wiki, the forum would be a "must-have". Kindest regards, Nikos