I tested the site at release time with current versions of Opera 9, Firefox 2. IE 6 and 7, and my PDA. The PDA did a worse job than I guess good ol Mosaic would have - but all the rest worked perfectly besides one glitch:
If you surf the site a lot, then register and want to post - you won't get posting buttons - the problem for this is referring to the browser setting of (don't know the english setting name) automatic new page check. So to get this to work perfectly, one needs to flush the temp-cache.
It might be the same problem, when switching back and forth between different editor-choices.
Kind regards / Peter