Extremely useful Rated 4 out of 5 stars
Highly configuable, tidy and above all very functional, this is my new favourite firefox addon.
It is incredibly useful in the office, being able to highlight working hours in different timezones is an excellent feature. It uses minimal screen real estate too.
My only suggestion would be a more intuitive way to show flags/alternative colours for all timezones, rather than having to do this one at a time. Other than that, it's perfect!