I compared my apple dual driver iems (purchase price: $36) to Sennheiser HD201's today.
The Apple is actually better overall in terms of clarity and instrument texture.
But -- b/c they're IEM's, they are more uncomfortable to use since there is pressure on the inside of your ears, and compared to OTE headphones something is lost by not using the rest of the ear's apparatus for listening.
And, since they use smaller drivers, for price/cost they can't touch full-size headphones, and frankly, the higher quality will be lost anyways when you consider that these types of headphones are used primarily on the go out in the world where, after a point, the noise gets in the way of any additional clarity.
In-fact, the apple in-ears falter a little bit IRL b/c they don't have overpowering bass to help drown out the surrounding environments, even though in quiet situations they prove themselves to be very nuanced.
Add to the fact that IEM's are on a whole more fragile, and paying more than $50 for a pair of IEM's is a waste.