[_ck_]

Well vbulletin is king-of-the-hill for a reason, many years of development, but it costs, costs, costs for everything.

But like I keep trying to suggest around here, bbpress’s easiest audience will be wordpress users, then next anyone who wants a more custom forum that doesn’t just have a vertical “brick” style.

In any case, if you poke around here you’ll discover there are have a dozen hacks and plugins you will need to make wordpress and bbpress work together more perfectly, but they are available and “proven” at this point. Look for the integration tag. I’ve been meaning to try to put them altogether in one post but keep getting distracted with stuff like paying the bills so the lights (and computer!) stay on… LOL

Forcing all logins through wordpress is possible (I do it on two sites now) but it requires a little bit of core hacks, which means the next time you upgrade it will have to be hacked again.

Forced login for entirely member only forums is also very possible, I believe there is a specific plugin or hack around here for it.