You can download the new monitor at http://www.xnet.co.nz/downloads/firefox/beta/xnetusage-1.3.5.xpi
In terms of new features, the new monitor adds:
1) The choice of viewing the standard breakdown or the detailed breakdown (displaying all Torrent information). We leave this up to you to choose which breakdown you want to see; just hit up the config options.
2) A line displaying when the last usage data got processed. One of the other engineers here has put some work into the traffic accounting system so hopefully we won't have issues where it gets half a day behind again, but if it does, you'll be able to see the time the last data was processed.
Anyway, enjoy, and if anyone does spot any showstopping bugs please do give me a shout!