Low frequencies quality of these ZX-1 is one of the strong points in my opinion: very linear bass response, with a very good extension down to about 27hz, fast and precise. Mids sounds open and with clear vocals. The upper part of the frequency range is a different matter. Highs are too much and it make the sound thin. Fortunately, a bit of EQ solves every problem: I set about -1.5db at 2k, -4.5db at 4k, -3db at 8k and -1db at 16k. But it's just a matter of personal taste. With the EQ, these ZX-1 sounds really balanced, natural and pleasant. Comfort is really high as they are light and not tight on the head. Imaging is very good, sound is airy with a big enough soundstage. The price for that is the almost non-existent isolation, so you will hear every environmental noise and other people will hear what you are listening too. NOT for bass heads. Unfortunately I can't compare them to headphones like Sennheiser etc, but I think these ZX-1 are absolutely worth the 50$ I paid.
They look ugly on any head :)