I am picking my M3 on Friday, and I have optioned the BMW individual high end audio (16 speaker, 9 channel amp, 825W). I think it's the same system as the EPS. I actually haven't heard this system, and the sales guy said that he hasn't sold this system before.
I have listened to the harmon/kardon system (13 speaker, 420W amp) in the demo car, and it was quite good. I think it's also known as the L7 system.
And I am expecting the system I have ordered to suitably better than the harmon/kardon ( especially considering the cost). I will report back once I have had a play. I consider myself to be an audiophile.