About a year ago I bought the HiFiMan RE-ZERO IEMs since they came highly recommended here. I loved the sound, but have since really regretted the purchase. The volume in the left earpiece dropped out, and I contacted HiFiMan support. We went back and forth through 21 emails, they sent me 2 replacement pairs but they all had the same issue. I ended up giving up, and now the sound is cutting out on the right earpiece (definitely seems like a short in the wire, although I'm not sure how since I take care of my stuff). I'm not sure if it's normal for CS to exchange for another product, but I'm really disappointed in how the RE-ZEROs have been. Is HiFiMan known for poor build quality, because I couldn't find anything about that when I was researching the RE-ZEROs. There was nothing but praise.