When I lost my Etymotic 4p's I bought the TF-10's. I could not wear the TF-10's -- too uncomfortable. I sent them to InEarz (Fisher Hearing) in Lake Mary, FL. (Now in Sanford, FL). I was pleased that they came back in a way that I could wear for long periods of time. They sounded great to me for a while but as I listened more and more I noted some problems. First, there is a channel imbalance slightly to the left. This may be me, it may be the TF-10's. I bought an amp with a balance control. That corrects the issue but I need to fiddle with it each time I use it. Then I noticed a "papery" quality to the midrange. I know of no better way to describe it. I replaced the cable with a silver cable from Audio Lounge (aka ChrisHimself). Ted makes a superior sounding cable. You need to be careful with it and it has microphonics but a plantronics clip and proper routing and that was taken care of. Sometimes, on some recordings, they sound spooky-real. They rarely fail to impress me and I am mostly happy. I have ordered the Heir 8a. Why? Did you ever see the original "Outer Limits" episode called "The 6th Finger"? Original air date October 14, 1963. It's too hard to describe but I want to push the lever all the way forward but this is what I can afford. I will couple it to a Fostex HP-1P if the balance is correct. This is getting expensive.