Mandriva user so some of this will not apply to other distros:
Agent still runs great under CXO 6.0.0. Both Pro and standard. Still no help files from inside Agent, but I have just discovered they will open in a web browser from CXO's menus.
Recently upgraded to the latest Mandriva 2007.1 and this fixed two minor annoyances with Agent under CXO on Mandrvia 2005. Not being able to change where downloaded files are saved via 'browse to' (cut and pasting a valid path was a work around), and forgetting the size of child windows on reopening. Yeah! Also introduced a new one. Can now only run tool bar icons at exactly 100%. Any other size renders them invisible. Tool tips still work and it is a great way to force yourself to learn keyboard short cuts:) Mine are now back at the default 100% until I find a solution.
CXO 6.1.0 unfortunately introduced a new problem. Agent runs but crashes on shutdown and will create a monster dump file if you let it. Almost twice the size of the entire Agent data directory on my system. Pretty sure there is a setting in Agent to not generate dump files. But crashing, even an apparently harmless crash on shutdown, makes this a very risky combination.
Have not yet tested CXO 6.0.1.