Thanks for help everyone. I have decided to enlarge my budget and get Vsonic GR07 BE. I am sure every IEM under $100 won't be much step-up from zero-audios. Technically they are very good IEMs, but the matter is that I am tired of its sound just like I can be tired of any other IEM's sound. So it is better to save money and do a bigger step-up. Thank you all once again.
12/30/14 at 2:22pm