What I mean by balanced is that I did not hear one frequency dominate the others. The was some punch to the bass, yet it was not boomy and it extended deep...the mids did not seem recessed...and the highs seem to fit in just nicely, except there was noticeable sibilance. I'm not susceptible to sibilance either - the highs of my GR07 and MS2s do not bother me at all. They had two or three RE-600 available...perhaps I should have listened to one of the other pairs to see if the highs were different on other RE-600s.
The RE-600 reminded me of my GR07. They could be a better GR07 if you toned down the highs just a little bit.