I got two pairs of the m100s. Wow are they terrible. The build quality is fine, but they sound like trash. Everything sounds muddy and deep. I have a pair of Brainwavz Deltas and they are unremarkable, but totally fine. I thought buying one of their higher end models could only give me better sound, but I was 100% wrong. I'm unhappy that I paid $25 for these things, so the idea that they sell for $90 seems absurd. I'll be sticking with my Deltas and trying to give these m100s away to someone who doesn't care about audio quality.