The mod names under forum categories often overlap the description text, in a way that makes the forum look a complete mess, other than that the theme is much nicer, however that itself is a rather big issue.
I suspect the issue is use of HTML5, which my browser does not support. Unfortunately me and many others can't use HTML5 supporting browsers because: We use Firefox for many addons that we need, aside from HTML5 - Firefox 4 and 5 are huge downgrades from 3.6.
Edit: I took a look in Firebug and I'm thinking it's more likely the CSS.