I just bought these as a replacement for my busted ATH-CK10. These are purely first impressions -- I haven't had near enough time with them for a full review. The CK10 is my main point of comparison.
Accessories - three tip sizes and--well, that's it. Nothing else. No additional tip styles, no case, not even a wax cleaner. That's pretty weak for a $400 IEM.
Build Quality - the housings themselves seem pretty durable. The green half feels like aluminum, and the seam between it and the gray plastic front is very narrow and even. The cable stress relievers at the housings are crooked, which seems like a clever idea, and the I-plug is flexible. The cable itself, though, is just north of mediocre. It has a slightly rubbery feel, but seems eager to coil and isn't as thick or pliable as I'd like. Maybe I've just been spoiled by the CK10.
Isolation - good. These aren't Etymotics, but it's pretty easy to get a good seal. I swapped out the tips for Sony Hybrids and the isolation is what I expected to get with the CK10 but never quite did.
Microphonics - terrible when worn cord-down. Over the ears, it's virtually nonexistent.
Comfort - they're small and lightweight, and you more or less forget you're wearing them. It's easier to get a good seal worn cord-down, but the microphonics are unbearable with that style. Cord-up is comfortable but takes some fiddling to get properly inserted. The shape of the housing doesn't lend itself to easy adjustment in the ears.
Sound - it's too soon to fairly evaluate their sound quality, but thus far I'm pretty happy. Compared to the CK10, mids are more forward, it's not quite as analyical, and highs aren't quite as sweet (that may just be my ears adapting to greater emphasis on mids). The soundstage seems larger. It feels a bit more musical and rich. If you liked the CK10 but felt it was just a shade too cold, these are probably perfect.
edit
I forgot to mention that these headphones are the most efficient I've ever owned. I've had to turn down the volume on all my devices and can hear a noticeable hiss on my laptop.