First off - http://www.head-fi.org/t/596233/buying-portable-or-in-ear-headphones-seeking-guidance-dont-start-a-new-thread-ask-for-advice-here
Going to copy & paste my own quote because a bit lazy and this happens to fit well -
Genres are helpful, but we all like different presentations of our genres. Stating sound preferences would be immensely more helpful in the long run. You can find a nice list of terms in the H-F glossary, but would advise against picking and choosing any term that seems appealing because in the end they might really conflicts with one another.
Describing sound is difficult to get into at first, but it makes giving recommendation a much simpler job. Otherwise you have people throwing out random suggestions for the only things they've heard, without much specification on what you might actually be looking for. A massive medley of choices can be just as confusing despite however helpful it might seem at first.
Also preferences in terms of comfort (any peculiarities in terms of fit that you might have with IEMs?), isolation, and build, would be helpful as well.
Know you said it's for a friend, so maybe you'd want to ask him about the preferences first off? Otherwise both are generally well-perceived and lauded for presenting those genres, but again, subject to preference, etc, etc, the above stuff. One just does it in a very warm and full-sounding way and the other goes for a deep and aggressive sig.