not sure about him but "Flashes in the pan" I dont believe he meant to everyone using phpbb, The way I put it is: Vbulletin is much more powerful than any other community software, you can tell that by this site. And phpbb is very good for little clan sitesfor a game. That is why a lot of phpbb mods include game server, clan rosters..ect..
I don't believe that the content or quality of a site is determined by the board software.
I think everything boils down to the admin interface and features. That's the difference. No ordinary user goes around looking for the extra features of vBulletin. As an admin, it all boils down to what kind of features you want your board to have... I don't think (in most non-technical circles) people are worried about whether you use phpBB or vBulletin.
I would use vBulletin if I could afford it, but the fact is, it wouldn't make one bit of a difference among my user-base. My community is determined not by the board software that runs it, but by the quality of content.
The other issue is technical. I am not going into the technical issues of using phpBB over vBulletin. That is a different question altogether and I am not a defender of phpBB in any way. In fact, if I could find an alternative to phpBB without the high price of vBulletin, I would choose that. phpBB has some issues: both major and minor, which I hope will be addressed in the next release phpBB 3.0 (olympus).
The point I wanted to make is, I would be very sad if somebody told me that the content of their board is entirely dependent on the underlying forum software they use. That would be the last reason why I would want to build a community.
In short, I think you can build a serious, mature community using phpBB as much as any other forum.