I never tested Amperior, however, I own Aurvana live and they are my favourite set in the kit (others I have HD 555, ATH M50, ATH WS 55, Philips SHN 9500, Philips Cityscape Uptowns, PX 100, PX 100 II, HD 238). I thought that ATH M50 won't be beaten on value for money front, but CAL are easy the champ. I use them, like all of my sets for the long walks out and about and their sound and isolation is simply joy to have on your head. Comfort is even superior to HD 555 and that is not easy to achieve (other then slightly over sized cups on HD 555.) Cups on CAL are, for my ears perfect as on - ear type, fully cover my ears to the edge and noise isolation is almost as good as ATH M50. I think that comparing to ATH M50 bass and treble is not as extended (just by a touch) but definitely sound more refined in both end of the spectrum. I like V shape signature, so middle, as long as it's present it does not worry me whether it's perfect or not. To sum up, for AUS $120 for twin pack (it's how much I paid for directly from Creative AUS) you 'd be silly to pass on brilliant set of headphones.