There are conflicting opinions regarding comfort with these two. I find the HE500's more comfortable for long listening sessions with the velour pads. The leather pads on the Audeze can make your ears sweat and if you listen lying down with cushion or pillow, the clamp pressure can be uncomfortable. Both are quite heavy but it didn't take me long to adjust to them.
What I find problematic is the fact that sound signature is going to change with both pads on HE500... Audezes leather and leather-free pads should both sound the same and therefore the FR graph still applies.