Soundstage: Audeze is more intimate and 3D. It's more spherical. HE-500 is more wider than LCD-2 and 3. LCD-2 and 3 have more depth and height than HE-500. Instrument separation is better on HE-500. HE-500 does better imaging near the sides, although LCD-2 has better centerstage and imaging. For me personally, HE-500 is more speaker like, and the easiest headphone to which I got used to.
Yeah, really good astute impressions. That's just what I hear.