Comparable to ER6i

They are of excellent craftsmanship headphones. I do not hear any difference between 6i and MC5, they are both excellent sound quality: its very clean and clear, well defined. At most, the MC5 have a slightly higher strength, the maximum volume is somewhat lower. The cable is also a bit shorter, but I found it too long on 6i anyway. It is enough to put a player in the pocket of his jeans for example.

The only "weak point" of MC5 is their size. They are bigger than ER6i, so they "exceed ears" somehow 'enough for long time wearing less pleasant than the 6i. On the other hand, removing becomes easier.