Well, I owned Amperior for a few weeks and returned because the bass didn't have enough good impact for me, the mids were muddy and highs lacked detail which made them harsh to my ears. I will be keeping the M-100s for life and I know this after less than a week with them. While there are headphones with bigger, deeper bass if you are a basshead, I would say that overall these are the best sounding headphones I ever heard at any price. If the M-100 was wrapped in wood and leather and I paid $1,000, I would feel very good about my purchase. They are a bargain at $310 and I consider Amperior overpriced at $350.
Awesome! Just placed my order! Unfortunately it doesn't ship until 60 days