Well, a little update. They have like 35 hours on them now, and they are starting to fill out. Also, I hooked them up to the T4 and Clip, which improves their already airy sound, but as noted in HPAddict's review, they are very unforgiving with lower quality rips and production tracks, especially the latter. Some of the older music I tested sounded rough. So even those these phones are inexpensive, they need a pretty high quality source.
If you got these for $63, they are a good value. And even at $79, they are worth it if you feed them with high production tracks, especially jazz, acoustic, etc. I didn't find them as engaging, for example, on some old Tom Petty tracks or Rolling Stones tracks. But not horrible, just not as clean, clear and airy as on more acoustic-based music.
I still on balance prefer the Grado SR-80s (tape modded), but it's gotten a little closer.
I tried both the NE-7M and the Icon Mobile, and sold both (the former just didn't feel comfy and was too bass heavy for me, and the latter could not compete with the T4 and I don't use a DAC). Not sure what I will do with the UF-30s, but I life them more than the other two NuForce products.