Got mine from loaner's program by Todd (http://www.ttvjaudio.com/), thanks!
Although I am probably unbiased because I didn't pay, no emotion attached. But be aware that my personal preference on audio is strongly toward flat presentation. YMMV.
So here is a short comparison with some other phones I have, everything are relative. It will help if you have one of those phones as reference point to mine.
The following chars are not objective, they are purely my subjective feelings. Only for comparing to your feelings on the same phone:
VSonic sounded to me is flat, close to reference, but the bass and highs are a little bit recessed. The sound stage is not very wide, but I do not care much about the size of sound stage. I care more about 'immersiveness'. Don't know how to describe it, it is a feeling that the sound comes naturally out of the inner part of the brain, instead of feed from the outside. It is a pretty good, and boring phone. Good for critical listening, not for fun.
HD580 (with HD600 grill) is a very enjoyable, all around. The frequency response is a little V shaped, adding fun to most of the music type. But it is a little bit grainy; not as immersive as IEM; the sound stage is big, but a little too big for my tast.
IE80's characteristics are similar to HD580. IE80 is also V shaped, but not as much as HD580 (I have turned bass knob to the lowest level, and I hope I can turn to even lower level). Since it is IEM, it has better immersiveness; the sound stage is smaller, but just right for my taste.
HE560 is at a whole new level compared to HD580. The details, immersiveness, speed, no grains at all. Very large sound stage, a little bit too large, but doesn't sound offensive to me at all, it is enjoyable. It beats HD580 from every aspect. Only if you don't mind the frequency response, the lows are fast and transparent, but the lows and the highs are not balanced.
Finally, Cardas A8. It is a very fine, and very fun phone!
1. Fine:
The smoothness is better than IE80, HD580. from low to high, there are no grains.
The bass is very fast and impactful.
Isolation is top notch, better than GR07 and IE80.
Details: for most of my friends, it has more details, especially in mids and highs. To me, my ears are trained by GR07, I can pick out more subtle details in GR07's recessed highs and lows. But for most people, for casual listening, A8 presents more details.
2. Fun:
Compared to other IEMs (VSonic GR07, Senn IE80) it makes all my music more enjoyable, I just keep listen and listen... To my ears it is a little bit more V shaped than IE80, which makes it fun, it brings life and energy from music. (To most of my friends: GR07 has NO Bass, unlistenable; IE80 has some bass, but they want more. And A8 has just right amount of bass.) The amount of bass is GOOD, but I hope the mid-low bass can be a little cleaner.
The sound stage is quite wide, which also contributes to the fun factor.
IEMs are for enjoying music on-the-go. Cardas A8 is excellent for the job.
