I haven't used phpBB from the admin side that much, but from what little I recall the adminCP is FAR more primitive than vb's, allowing far less control. On the plus side it's probably easier to learn than vb's.
I wouldn't say phpBB is better but it certainly is a worthy (open source) alternative. JP has a point about the admin side, especially with huge user database.
phpBB is easily customisable, cost free, great community and support, pretty much offers what vBulletin offers. I didn't see any "quick reply" option, but it might exists as a "mod" (which is a really cool part of the admin side)
Only buy vB if you expect a huge number of users, otherwise phpBB can handle it well
vBulletin if you can afford it, otherwise phpBB. PhpBB contains many of the features of vBulletin only without the hefty price tag, generally speaking phpBB is more then sufficient - just remember to upgrade regularly to avoid bugs.
I use to use phpBB all the time and still like the software but it is a huge bot haven. Of course you could fix it yourself but the developers should do that. Now I use SimpleMachines Forum or SMF - www.simplemachines.org it's a cool board with more features than phpBB has. You should try it out, of course it is free
I have yet to use vBulletin but I might one day...
i've used phpbb mainly because it was free but vB does give you more control and had way more features than phpbb of course can be modded but had compatibility issues with certain mods. i say for sites just starting out phpbb if your still developin and so fourth but once it starts to grow upgrade to vB as i will be doing soon.
the basic difference lies in cost....while phpBB is free vBulleting cost arnd $85 for one yr license fee....i used phpBB and on every aspect it failed to match vBulletin....be it Admin Panel, Looks or User Friendly...
but being free it equals everything...one of the major drawback is no quick reply box and the page thts displayed after posting a reply...although quick reply box is available through Mod but still....and nothing for tht page...
but must say phpBB is highly customizable and yet free