They all have a different feel and emphasis. A Flame wars break out every so often but overall it's a supportive place to hang out. People are very willing to help out with questions and concerns. This is a popular moderated, web page based forum. Rather less infighting than on ASMS but overall a similar scope.
Registration is free.
Jooly has put a lot of work into her MS WebPals project and has won numerous accolades as a result. Registration is free. A few people from elsewhere visit but has far fewer posts than the above forums. Registration is free. Registration is free.