I think they're worth it. I always take risks on lesser known headphones bull and I'm glad I picked these over some Senns I will tell you they need some juice though, not as much as the 701s but I can't listen to them at an acceptable volume through any of my mp3 players. If you've got any sort of decent amp though you should be fine.
They do need an amp, and I am generally reluctant to say this. They sounded really good from my little Pico Slim, but I could max the volume on the Pico Slim (roughly 175mW per channel). I have an iBasso PB2 that drives them very well single ended, and balanced soon to come after a recable.
Many here recommend a desktop amp. I'll go on record that there are portable amps out there that will drive these very well.