I've checked the other drivers so far and they all seem to be ok sounding to my untuned ears. My ears are only able to detect distorted sounds or no sounds lol. Everything else sounds great though. I haven't borrowed the Denon 6500 yet so still using the Sony 1080 and it honestly sounds pretty good. The VP180 has really shown me how much I have been missing on the vocal front.

M60
VP180
M2i
Sony STR-DN 1080