In the stores where I saw both the Panasonic and Samsung plasmas the Panasonic looked better and exhibited nothing unusual relating to the skin tones. Also note(library?) the outstanding results they achieved in the recent March Consumer Reports tests.
Since I haven't heard either the M80s or the EP600, I can't speak to the comparison you propose, but you may have read previous posts here decribing the extremely high rate of satisfaction with each.
My preference has always been for a vertical center for wider and smoother horizontal dispersion rather than a horizontal MTM configuration, but again I have no experience with the TMMMT configuration of the VP150.
