It looks like vBulletin has a calendar and an administrative statistics page. I had to go in the admin demo to see this. In phpBB you get a much bigger community making mods and it's free to use and upgrade forever.
So vBulletin seems to have a few more features, but you pay for it. I can't comment on the robustness of it. So I guess it's the old trade off of commercial vs. free software. Do you want to pay for commercial support or not. Also, vBulletin has threaded instead of a linear mode like phpBB.
phpBB is a high powered, fully scalable, and highly customizable Open Source bulletin board packBage. phpB has a user-friendly interface, simple and straightforward administration panel. Based on the powerful PHP server language and your choice of MySQL, MS-SQL, PostgreSQL or Access/ODBC database servers.
vBulletin use template style of XHTML And CSS. Also a WYSIWYG editor for users to post in.
Hope this helps a little bit.