0.2.17 works just fine on FF 3.0 Final Rated 4 out of 5 stars

4 star rating because the extension works great, but could be prettified.

Values like CPU Usage and Bandwidth should be zero padded (01%) to prevent the statusbar from constantly bouncing to the left in non-fixed width mode. Some fixed-width in non-fixed font compromise should be possible as non-fixed fonts still have fixed-width numbers.

This review is for a previous version of the add-on (0.2.17).