I have the Etymotic ER4-P/S, the Shure E4C both in the $300 category.
I also have the Etymotic er6 and er6i arounbd 140 dollars each.
The ER4 is veryyyy flat, no coloration or boomy bass. So they are perfect for people that want to hear the music the way they are meant to be heard, and like you say classical is good example of this.
The shure is more dramatic and would suite the "popular" taste of pronounced midrange and strong bass. I found it funny that the cheaper ety er6 also has this charactaristic.
All in all they sound incredible, but they are definately created for different tastes.
ETY ER4= flat reponse, critical listening, less bass
SHURE E4C= good for popular, non classic music, lots of bass and pronounced midrange
ETY ER6= fairly cheap, same charactiristic of the E4C, but at lower price.
So someone with an ipod will enjoy the ER6 or E4C. While a producer or person that likes classical will enjoy the ety er4.