after listening them for some days, without touching the xb500 i just listened both on some different music tracks and styles...
well i have to say that even if xb500 is a really great pair of cans, m8 just rocks in almost everything... even the basses...
the sound clairity is comparable to mdr v700dj, that is far more superior than xb500, but the bass is powerful and punchy like xb500 but "cleaner"
i only prefer xb500 for comfort, even if m80 are very light, they start to "hurt" after an hour, my ears become warm but i definetly could sleep with them on, so not a big issue.
i can only say wow. great pair of cans, absolutely satisfied, especially for the price, 100 euro shipped
isolation as i said is great, with music at low volume i can't hear almost anything around me (not in metro or on a bus)