Just had a look at http://www.novell.com/linux/index.php
in various browsers myself. Indeed, I get to see the innocuous version under Mozilla and the knives-out-for-Red Hat version on Firefox. I have also given Opera and IE6 (under CXO) and Konqueror a go. The first two get the friendly Linux site, but Konqueror gets the same as Firefox.
I wonder if this has anything to do with the identification string the browsers send, as in whether they flag up that you're using Linux.