It's split among states. By the time I got involved, only MS was available so I do it for our Tennessee/Alabama office which only does Dynamics NAV.
Yes, its super 'salesly' and I'd say 85% of their posts are in that category. I also am very impressed at the volume of content they get from their members (but they have no socialcast like collaboration, purely group blog)
Us two being active bloggers, it very much impresses me how much content they get from their members. We know 90minds.com and other ventures where 90% of the posts come from 5% of the members.
The cost is fairly low, like $50/month and they have a person (Anya), who's very dedicated to running it. They also do weekly webinars on SEO, etc. Microsoft likes it and cross posts the content on one of the microsoft blogs which gives it strong SEO value. (google erp software)
Most of the leads they capture are the automatic reverse ip search type where you get a company name, location and public phone number based on the IP of the viewer. These are distributed based on the 'state' you 'own.' I've not gotten any business from it, but I don't know if that would be different if I had a useful state like NJ or NY.
They have a few other group blogs now, mostly microsoft centric (one for CRM) but this is definitely the highest volume. It also adds link juice to your own website because you can refer back to your own, and they are 'follow' links, in your blog posts.