They do sound nice but i have just bought the M50's and comparted to my old phones they sound just brilliant. I like the bass on them as it's not to heavy and seems to fit in with the type of music i listen too (female acounstic - Kate Bush etc), the idea of lots more bass may not fit in with what i am after. If i get a chance of listening to the MK2's then i will do but for now i think my M50's should be just fine for now/
Trust me, that is a good mindset. Keep what you have. The M50's will always be superb.