Forum switch?

Lately I've been looking into merging my existing phpBB forum with my Joomla site. Ideally, what I want is to be able to just embed the forums into my site (visually) without merging their userbases. All the "bridge" extensions I found on the Joomla extensions site seem to involve merging the db's though. I'm not sure I'm ready to take that step yet.

I'm also considering switching over to an SMF (bridged?) forum-- that's what the official Joomla forums is running, so it must be good, right? ;) But I've never used SMF before, so it's a little scary. (Well, not really, but I don't know if it's worth spending the time to try it.)

A third option is installing a Joomlaboard extension. It seems to be the cleanest solution, since it's apparently a native-to-Joomla component, not a bridge. However, I haven't investigated it enough to know whether it's as full-featured and relatively bug-free as the other options, which (I believe) have been around considerably longer.

Since I'm fairly particular about how my forum software works, and what features it has to have, I'll spend more time considering all the options before making a decision.