yeah you wont beat php....less buggy

Vbulleting is far the best one to go with but it is not free. If you are looking for a good one that is free then phpbb is a pretty good one.

I think VB is the best when it comes to features and security.

I also believe VB is the best.

I've always used SMF and have never had any problems, and it is VERY customizable.

Never been a fan of phpbb because of the security problems with phpbb2, and I never liked the look of it although I have heard that phpbb3 is much better.

SMF 2 should be out later this year and so far looks great!

In terms of "integration", I find Phorum the best of them.

I heard that with PHPBB your are very likely to get hacked if your site gets big. Havn't really heard much about SMF.

I highly reccomend AGAINST smf, it has many flaws and it is annoying to update, phpbb on the other hand is easy to update and the new bbcode option is awesome

To add my views and advice in choosing forum software, i would give my vote to phpbb if you dont want to spend, and vbulletin if your pocket allows you.
IPB is also a good choice but i think vbulletin made a trend.