If I could use one word to describe the sound of UM Miracle it would be Poised. Feed any genre of music to it, and the Miracle will present it with an admirably poised manners. The balance of the frequency from top to bottom, the natural tone and clarity presented in an immersive soundstage really gives me the cloud nine listening experience, and the fact that this is an IEM means I can have this listening experience with me everywhere I go. Overall this is one of the best sounding audio gear that I’ve experienced to date and will definitely remain so for years to come.
 
Full detailed review:
http://www.head-fi.org/t/604652/review-unique-melody-miracle-a-personal-take
 
To summarize, here are the list of what I think the Miracle might and might not be preferable.
Preferable traits:

1. Balanced frequency response and natural tone
2. Versatile and visceral bass presentation
3. Sparkly yet smooth and refined treble
4. Midrange presented with extremely good resolution and texture, and excellent vocal presentation
5. Overall poised presentation and grand soundstage that rivals high-end full size headphones
6. Sounds great with wide genre of music and just about any audio source

 
Might not be preferable:

1. Depend on budget, it might be pricey for some
2. Full acrylic shell might need sometime to get use to, some might not like the feeling of it
3. Not for basshead, not tuned for typical club banger
4. Not for vocal junkie, doesn’t have that thick, warm, and forward vocal presentation
5. Not for people that seek absolute flat frequency response or uber detailed presentation