Top marks to Phonak for producing such a high end IEM earphone for this price.
The sound quality rivals many of the big boys and walks all over the Sennheiser IE series and Bose in-ears. The PFE digs out all the detail in your music you are missing with inferior earphones.
Phonak have got the in-ear fit perfect with the PFE. The earphone just sits in your ear, with no wait on the ear canal. The over-ear cabling is very clever. I'd never heard of Phonak, but doing my research it seems they know a thing or two about the ear (over 60 years developing hearing aids).
The sound quality of the Phonak PFE 122 is exceptional, with loads of detail and accuracy. Bass response is on the light side with the fitted grey acoustic filters, but by swapping to the black acoustic filters it's more chunky. I've since upgraded to Phonak's new green acoustic filters and the bass is now powerful (in fact I'm not sure if I prefer green or black filters).
The PFE 122 is very nicely made, with a durable earphone body and robust cabling that has some kind of tough coating to protect it (according to posts on head-fi.org they recently revised the cabling).
If your upgrading from cheaper earphones (e.g. Sennheiser CX300) the sound quality will blow you away!