I upgraded from the 500 to the 600 and have no regrets. The 500 did just dandy, but the 600 simply outperforms it without question. Surprisingly, the biggest difference I noticed was stereo playback. It’s amazingly smooth and tight and blends extremely well with the M80’s for all music. If I can ever save up for a gloss black 600, I will be replacing the Outlaw LFM1 with it for my two channel system.

I would say just get the 600 if your budget will allow it.