I already said before what I think about "all-in-one" server. I think this should be one of the main arguments, but at least as important is the scalability, flexibility and the modularity of NethServer.
I agree that on sites as Distrowatch.com, Alternativeto.net etc, all the different services should be mentioned, and not just "all-in-one" or "Small Business Server". People get to these sites because they search on UTM or Gateway, Mailserver, Fileserver or Printserver. Then these keywords should be defined in the NethServer profile of that site so NethServer pops up when such a keyword has been entered.
To add to @Jim's list, I will add my 'other distro' that is the complementary server of the GW/UTM distro's: Karoshi Linux. It is all (plus a lot of educational services) NethServer can do but lacks a GW/UTM.