I can't say too much since my experience with Citrix is quite limited. Like you, I inherited it, though I use that term loosely. It's mostly that I happened to use it to get Windows services on an old Solaris 8 box, so I became the defacto Citrix guy.
Anyway. I would say it would depend on what your purposes are. If you're virtualizing applications only on an '03 server, you'll want to stick with Citrix. For plain ol' remote desktop on Windows/OSX, there's not too much need for Citrix aside from a few value added things as both have native RDP clients. Citrix does have some nice tools and configuration capabilties, but again, they're more along a value-add than a requirement that doesn't really start getting a return on investment unless you see some heavy use.
Here, we now only use Citrix services for remote desktops on Soalris 10 thinclients. The servers are pretty old, so we're on a push to get them consolidated to one (or two if we can convince on redundancy/clustering) servers running terminal services only. Solaris has an RDP client that works fine, so there's no need for Citrix clients to initiate the remote sessions.
Note I don't have any experience with the newer Citrix stuff, nor Citrix on 2008 servers. I'm also assuming remote desktop services or OS-native RDP clients aren't prohibited via group policy or some such like it is here. That's our major hiccup -- we don't control the domain, so plain RDP logins are prohibited. They pretty much REQUIRE us to use Citrix even though we don't have a need for it.
Anywho. Hopefully someone more experienced can come along with more info. I'm curious myself since I haven't done anything with the new Citrix products.