I had m60's for a few years and now m80's, my room is 8,000 cu ft and they both sounded just fine, I would not say there was a huge difference in the sound at normal listening levels. When you start to really crank things up to insane level that most don't listen to, the 80's do better.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85