I've heard that V-B is more secure. Two Phpbb's that I know of that got hacked:
1)Gameedit.net: Nightmare rebuilt Gameedit.com using phpbb and it was going well, then (according to him) hackers took it down. He rebuilt using V-B.
2)6DOFbb.com: Koolbear created 6dofbb, I guess he got tired of running the DBB, and he wanted to be open to other games as well. It got hacked. It is still there, LOL! But there has been no activity since being hacked.
I like the easy modability of phpbb, but that same modability may be the reason it is more susceptible to attack.
a couple of other phpbb sites, that did not get hacked: Decentforum.de, and one I admin:
pack270.us forum board. This is a Cub Scout form, I have two public forums and they get a lot of spam, mostly porno links. Today I deleted a user who tried to sign up using an email "
[email protected] ...yeah right, I'm gonna approve that one!
Disadvantage I see of VB: you have to pay for it. I don't know what their policy is on upgrades, though.
Another possibility is there is a mod for wakkawiki to integrate with phpbb, if you have ever considered adding a wikki.
Please list your reasons for considering a change.