Ive used ipb, smf and phpbb they were all pretty good imo theres not a whole lot your forum needs to do really vbulletin is the most secure and has the best mods though imo
I've never once been exploited or hacked with phpBB. I have had active forums throughout 2002-today. I see them hacked when people don't update them.
Yeah, I didn't have mine hacked as phpbb. Spammed, but not hacked... lol. Like Jackuul said, I think it's fine if you keep it updated.
Well, the question here was 'which one is better' - the answer has to be vBulletin. If it was, which one is better value for money, then that could have a different response.
I am running phpBB right now and there are plenty of bugs. Also there are SOOOOO many spammers. Its a pain to set up stuff to keep them out.
I highly recommend installing the mods: The Humanizer, and related. These are rather easy to install and circumvent the scripted bot attacks. Any forum can be bot attacked - it is rather difficult to control them I have to admit. Thus far however, I have been extremely successful.
As much as I love vBulletin, I think soon it will be overtaken.. I can't see where vBulletin is going anywhere. They're running out of ideas..
Definetelly, vbulletin is better. It's very very secure, but costs. Basically, the a non mod-ed version of vbulletin is like a fully mod-ed version of PHPBB.