Thought I'd bump this old thread for all you with a wad of Christmas $$$ burning a hole in your cargo pants.
First off, I have a Jayes D-jay, various koss 60 ohm cans, modded plug, e2c, SR60/40, FX33 and borrowed a PK2 from nankai for a month. All are very good portable cans at the $100 or less mark, and have their strengths and weaknesses.
I have to say, after half a year with the EX90 and its all said and done.... the EX90 has somehow become my favorite portable can. It has managed to quietly climb up my can-ladder and position itsewlf at the top of my portable-lineup. Its more open sounding than any IEM in its price range. It packs enough bass kick to come close to a modded KSC75. It cant touch the KSC75 in terms of spatial image separation, but it makes up for that with a more focused sound that really pulls you into the music. It also doesn't have the lower midrange recession of the KSC75, so its warmer and less harsh... while still retaining detail.
How's it stack up against the SR60? Ooh tough call for this die hard Gradohead
As a portable, I find the SR60 just doesn't have the isolation. The LOVELY Grado bass slam gets lost and sinks like a lead balloon in a sea of background commuting noise. The EX90's slight isolation is just enough to keep the music in and the noise out.
The really nice thing about the EX90 is that it can easily be modded to fine tune the taste. Want BASS+isolation? Seal up the enclosure vents with masking tape. Want more mids?... remove the foam and cloth tube cover. Shweeeet!!
Out of the box, the upper mids are a bit recessed, compared to its stellar treble response. But thats where the de-foam mod comes in to bring those mids in line with the treble.
I found them to scale up very well with amplification too IMHO the bass tightens up a little with my pimeta. But thats relative to my unamped sources. So, I even use them at home with my pimeta.
The EX90 is the ONLY in-ear headphone I have used that doesn't significantly change its sound signature the deeper you RAM it into your skull. I use medium tips and just place it gently against my ear and its an airtight seal. Hands down the most comfortable in-ear I have used.
Thanks and happy listening!!