These headphones are better than any headphones I have auditioned. No cons at all.

Some people say it lack bass. They are wrong definitely. Their bass is just right!

Better than RS1i, HD700 and K812 in most aspects.

This is the first time I give a lower than 5 star rate. The reason I say tha K812 is not good for music listening is because K812 seems to has it own way to illustrate music: it seems like K812 likes to confine every piece of music in a certain room with a stress of bass. This is good because that will ensure you hear something familiar every time you use K812. The strong signature is definitely for pros who do not want to waste time getting familiar with a headphone again and again.  But for those who are not basshead or those who want to hear "music free in style", this strong signature is a big big big problem. 
 
The sound is a bit dark, detailed but no way balanced. To much bass; imaging is good in a bad way (Clear, wonderful imaging, you can see everything but the singer seems to be in an awkward position: behind/is the drumer) treble sounds uncontrolled like hell if you don't drive it properly; sounds depressing as if I was listening via closeback phones
 
 
 
 
Bottom line:  Remember these are monitor headphones. Don't waste you time if you are not a pro. 
 

This is the amp I am looking for. It is better than any portable amp which costs around 200USD.
 
It can substantially enhance the soundstage, the speed and the bass of your headphone.
 
I am using it to drive my RS1i and it's perfect. BTW, It works great with any device I plugged in.
 
I even tried apple's earbud and it suddenly become my favorite earbud.
 
However, I still hope you can distinguish its quality with your own ear rather than sb. else's reviews.

Good headphones. A great contrast to SR225i which is cold and calm