I'd just like to add to those that often scoff that I believe that a practical EQing system such as this one can simplify the complex choices needed to make repeatable results in different environments.
Used as a tool toward that goal then ARC is a good system, despite many of the shortcomings that are often cited which are based on some truth, there is nothing currently on the market that comes close to ARC on bringing as much control of such a big variable as equalization of the surroundings.
So yes it doesn't take into account the exacting standards required by elephants, nor control discrete elements of a playback system but it does make a good judgement of what is happening at the listening position and calculates accordingly.
Even I can see that and I don't use it, I tend to best guess the foibles of my own particular environment from experience but I can certainly warm to the appeal it has to many by arriving at a decent ball park from an EQ point of view in a quest to find a way of producing repeatable results when mixing.