[Envoy of Light]

Hello everyone,
I am looking for a new pair of IEMs for my portable needs and I cut down the choices to either the Westone UM1 or the Head-Direct RE2. The two major things I need from my IEMs are sound quality and noise isolation. Regarding noise isolation, I realize the Westones will isolate more, but I don't know exactly by how much more. Is the difference in noise isolation between the two IEMs I have stated significant?
And regarding the sound quality, I have no idea which IEM is better. I listen to Rap, Hip Hop and Punk Rock, and I want the best sound quality I can get(between the two IEMs). I am going to use the IEMs unamped, from a Cowon D2 or a Sony A729(haven't decided yet). Which is going to be the best choice for me?

Thanks in advance, I really appreciate your answers!
Have a good day,
Envoy.