RedCats on Green or Blue, a matter of taste, what counts is: the cats are red Rated 5 out of 5 stars
What I have written about the Redcats on blue applies to the Redcats on green as well.
Personally, I simply choose Redcats on green or Redcats on blue depending on which of them matches the operating system's colour preset best. Currently this is Redcats on blue for Windows and Redcats on green for Linux. But it will always be Redcats. :-)
(currently RC5.5.2 on FF11.0)