With regards to browser compatibility, Opera have recently released a beta version of their browser, it appears that this beta renders MacIRC perfectly, unlike the current stable release (8.54 at time of writing) which has a few issues with the site, however still renders it well enough to be of use.

Therefore, I would recommend that Opera users update to the latest beta for viewing the site.

This now means the only browsers to render the site 100% perfectly, as intended are Opera and Safari. Firefox/Gecko still has issues with the clients page, which I believe to be a CSS2.1 issue.
Comments are not enabled on this article
Render: 0.0071s
Check: XHTML, CSS2, RSS.