Rated 4 out of 5 stars
Working in FF 19.0a1 32-bit on win.
It's a good alternative for restartless CSS Refresh, non working for me.
The main drawback is the size beyond 100KB, it's probably made from an addon development kit. The keyboard shortcut, overlaps with F6 of FF for focusing the adress bar, but at least it's configurable.
Alternatively you can use the restart required CSS Reloader, only 3,5 KB.