First of all, that isn't an apples to apples comparison. XenDesktop lines up with Remote Desktop or variation of (a complete Desktop, from which you can launch multiple apps, etc.) RemoteApp is ...

I need to test Windows 2008 Terminal Services/Remote App as our old (Windows 2000 plus Metaframe XP) TS box won't run the latest dotnet which means we can't run some new applications that we want to.