The quality of sound and production is indeed rather good for in-ear headphones (although not to be compared with Shure or Etymotic), but the idea of bass-driven in-ear headphones which actually get stuck inside of your ear canals doesn't only sound but has proven for me to be complete bullshit. You cannot walk around with these things in your ears 'cause every single step, every brush against the headphones cables are transmitted straight into your ear and are reflected as dull, crumbling noise. And seriously, what's the purpose of these things if not going out and exercising? After a few hours, my ears started to hurt and the headphones were a case of the waste basket.
My suggestion: If you can live with such noise, buy them - if not, stick with cheaper classical ones.