If you run RedHat Linux or other open source flavor... you should read this article. I think it does a good job of showing some of the differences between the two platforms if you didn't already know them. I'm sure lots of you brilliant system admins know these things... but I know that many of you probably assumed that these operating systems were only marginally different.
If you ask me, there doesn't appear to be anything marginal about this:
http://www.osnews.com/story.php?news_id=580&page=all
Cheers,
Brad