It does look nicer. C'est trés bon. It's at 3.0.03 now. GreekChat.com currently uses the very latest 2.x type available.
That said, it can be a pain in the ass to upgrade such things. It isn't just a matter of installing the new software (although that is a big part, heh). You also need to reconfigure all the settings - hopefully that sorta stuff autodetects/uses existing settings files but you do need to keep an eye out to make sure. A big issue is add-on scripts if installed as
they have to be reinstalled as well. For example, one script used here (unless it is now part of vBulletin as standard but was originally used as via a script here at least) is the front page feature where it lists recent discussions on GreekChat.com? I am relatively sure it is still an add-on script. Inevitably John would need to make sure that script was at all version 3.0 compatible version or it would need adapting. That may or may not be possible.
Version 3 does offer some impressive features and administrator options. A lot of cool things. Many of these (well all of them in fact) may be enabled or disabled by the site administrator. There can be all sorts of reasons for each decision. Many exist in version 2 already and many new 'features' are cosmetic. Features:
- IP address searching by addresses used by user (admin).
- Ability to move users between groups including mods/non-mods but also unregistered users, awaiting email confirmation etc.
- Avatars and also Profile pictures [admin-defined or custom: uploaded from own computers or to a URL specified].
- Ability to set avatar display width plus enable/disable custom avatars (we all know they'd be open to abuse!).
- Enable Thumbnails for images in posts so users can click on thumbnail.
- Enable RSS Syndication for feed of latest threads in specific forum(s) to read it via external pages/journals etc.
- Search Relevance Scoring. So when you search you are told e.g. by percentage of relevance to search terms.
- Polling (available in all versions but they've probably improved it, sometimes not a good idea to provide at all as it leads to 'campaigns' - drama).
- Quick Reply, a box will pop-up on the showthread.php page allowing users to reply to the current thread without needing to load the full newreply.php page.
- Option to prevent users 'shouting' in their thread titles/message text by changing all-uppercase titles to capitalization only on the first letters of some words.
- Time to Wait Before Starting to Display 'Edited by...'.
- Global ignore: Allows administrators to effectively add a user or users to every member's 'Ignore List'. However, users in this list can still see their own posts and threads....
- Troll management: 1) Email validation, so email has to be working and valid. 2) Registration moderation, to accept/decline registrations before they're given permission to post. 3) Each post stores ip address, so IP can be blocked so user eventually runs out of ISP hosts & proxys. 4) Banning email domains. Generally what was available in earlier versions; the global ignore feature as a default option is new though.
- Members List Searching.
- Private Message filing in custom folders.
- Allow Users to 'Ignore' Moderators (oh hush :P. There're plenty of reasons for not allowing it. Ever).
- Allow IMG Code in Signatures (don't even think about it ;p)
- Maximum Characters Length of Signature (glory, glory alleluia). It's also possible to limit # of lines used but not as standard and this entails John being hacky
.
- Using 'conditionals' to cause each user's signature to be shown only on their first post on each page.
- Censored Words - asterisking. Heh, this was once enabled on GC. Didn't last long though - you bad boys/girls
!
- Moderate New Members so posts have to be approved for public display. Very hard to manage on high volume forums, someone in person has to approve privileges, useful for trolls in theory though.
- Specify max width/height/filesize of uploaded images, so for instance users can upload say JPEGs up to 600 x 400 and up to 75kb.
- Easy board FAQ editor.
- Help Smilie Manager to add new ones.
- Pop-up auto-refreshing buddylist with ICQ-style alerts when new buddies come online.
- Mouseover thread summaries.
- Various styles for IowaStatePhiPsi to play with. phpBB is limited & much less advanced than vBulletin.
Inevitably hacks (unsupported add-on scripts that can cause more hassle than they're worth) are already available for the new version e.g.:
- Auto Resize Image Attachments uploaded by users (avatars & profile Pic too).
- Maintain a database of quotes which can be added by users and displayed on homepage. Admin function includes ability to delete quotes from database.
- Disable swear censor per forum etc....
All that said... bandwidth can increase (exponentially) from say 80-120gb bandwidth a month to a lot higher with extra optional graphics. Only John knows how much the site uses. Bandwidth is one of the most expensive elements for a site.
To give you an idea of this, LiveJournal.com while admittedly a larger site has paid as much as ten thousand dollars for bandwidth costs in the past. Per month. It is their biggest expenditure; more so than hookers and blow for the staff.
Plus, more (MySQL) disk space on server would be taken up with avatars if implemented so this has to be taken into account. Then there's lost opportunity cost. The site would be offline during the upgrade but also installing the new version would take a little while - John's time is money of course.

It's 30 bucks per year once you have an owned license (owned license allows you to run the software forever) to access upgrades/new versions; I presume the upgrade licence is still valid but if not that's $30. Not a lot but still.
It's perfectly possible to set up a (private - admin only) testforum to try out everything first. But the issue is of whether it's really worth it for the sake of shiny things. I'm not saying whether I think a new version "should" be installed or not. It's not up to me (obviously!) and many of the changes are cosmetic. In some ways it would be nice but of course we don't have to do the hard work and spend the time doing it.