Pros: Detailed, balanced, realistic sound, build quality
Cons: Various fit, sometimes too sharp highs, useless on freeze
First of all I rarely listen to them apart from my rig that include iPod Nano 6 and RS Audio P-51 Mustang. After years they stand the time the best from whole system - none of cable wear nor plastic damages even jack plug still has pristine gold shine. But lets get back to the beginning...
My very first impression about them during listening The Doors was that Jim sings as if my ears were a studio mic and his mouth few centimeters away. It was so intimate yet detailed like never before, it sounded exactly like voice of living person standing next to me! Even later I couldn't believe how sweet Kate Bush or Stevie Nicks can sing. THE vocals. This is definitely the ultimate strong point of Phonak's Audeo PFE 012. Unfortunately I almost didn't hear any bass. May be it's to much to say, I herd it for a few minutes before original silicone plugs change position in my ear. At that point I would rate them on 2.5 stars. Luckily I tried replacing original buds to Comply foams and this changed whole my life.
The foams solved fit problems and warmed a sound, defined a soundstage and overally improved sound quality and comfort at the same time. Bass is really deep (this mainly depends on proper fit) has both nice contour and attack and body. I would describe sound as warm but natural, only high pitch or guitar can rarely hurts. Really pleasing experience to listen to remastered The Who, Yes, The Beatles albums. They are not as incredible in electronic music but still a wild thing. And I love concept inserts like telephone talks or binaural recordings -- these ear-phones present such experiments in totally realistic manner! (Every time a telephone is going to ring on Surgeons Force+Form album I wish he wouldn't answer the phone!)
Recently I had a period when I completely stopped to use them and I started to look for full size phones. I did some sessions with entry level Beyerdynamics and Ultrasones -- non of them convinced me. I gave a try PFE's again and that was my sound I was looking for. I didn't buy full-sizes, I understood I wouldn't find anything as good in this price. Phonak discontinued them (with others phones as well) but I believe I've get the cream of the crop of entry level portable Hi-Fi.