Red Hat Fedora vs Enterprise Linux WS vs Desktop

[Adam Boettiger <adam boettiger pobox com>]

I almost hate to ask this question on this list, but I've looked in the 
archives and can't find it.  I've looked at this chart here:
http://www.redhat.com/software/rhelorfedora/

My question is:

Other than getting the paid support, is there any real reason to buy 
Redhat Enterprise Linux WS or Redhat Linux Desktop as opposed to just 
using Fedora IN A DESKTOP ENVIRONMENT? (not a server)

The comparison chart doesn't really do a great job of prompting me to 
take out my credit card.  I don't get it. Is it just that the commercial 
versions are supposedly more stable and have more packages available for 
them or ... ?

If this question has been asked before, just tell me so and shoot me the 
URL off-list or on-list and I'll happily RTFM, but I have looked and no 
can find.

AB