Maybe I'm just not used to it yet, but I liked the way Vimperator did it: having the hinting number also be in yellow made it easier to see.
It's possible there are ways to configure this; I haven't checked thoroughly yet.
I had continuous problems with Vimperator on FF4, thus far Pentadactyl's been a bit more stable although occasionally it seems to get deactivated altogether and I need to restart the browser.