These work for certain applications, basically those that print the rendered frame names to the logs, and also AfterEffects and Cinema4D.
As well, the QubeGUI can only display certain file formats, so you could have "Browse Output Dirs" work, but not be able to use "View Output". The most noticeable format that can't be displayed by the older QubeGUI is EXR's.
The new ArtistView gui ~can~ display EXR's, and it has a nice "scrubbing" view, so you can move a slider and scrub through the rendered frames.