I am totally new here. I live on a fixed income so I cannot afford stuff, but a good friend in another forum gave me their trusty old Cowon D2 and the other day I fixed a friend's friend's computer and was given the gift of IEMs in gratitude. I am very thankful for the OP's detailed reviews, I chose the iMetal iM-590s. When I first used them, the bass seemed a little weak and that there seemed to be sibilance (from an uneducated ear) in the uppermid, low treble, but nevertheless they sounded outstanding.
Well, I was skeptical, but I did a burn in using this website here: http://jlabaudio.com/burn.php (I don't know if there is anything better, if there is, please let me know) for 12 hours after listening for 4 hours.
All I can say is Wow. After finding a better fit (I am still trying to find the right one for my left ear which is smaller than my right ear), the bass is just right, mids are clean, treble is crisp, and it sounds like I am there. I used to have a pair of Sure E2Cs and they were "blah" to me, but these are terrific and only 44 bucks at Amazon. I spent a whole day working on a guys computer but it was worth it to have these.
I know you audiophiles out there will chuckle at some noobie with no pocketbook, but I just wanted to thank the OP before I dig in to the forum and this thread. So much to read.
My roomate gave me a lot of ribbing about headgear thinking it made little difference, until he listened with these. He just isn't into music like me, I used to be in a band (those were the good old days).
One thing the OP might want to add to the review of these iM-590s is that some complain that after a while the internal wires start to pop out of the woven cable cover and can't be coaxed back in. Probably people who don't treat their stuff well, but I am going to watch out for it.
BTW, stuff played in Rockbox definitely sounds better on the D2 than the native OS.