i bought the dt990 pro, they're really comfortable initially and long-term, though you might run into issues with the earpads getting in contact with your ears if they're really big
they also sound really interesting, both the treble and bass speak for these headphones (which is fine if you like it) and playing from a source like the schiit magni 2 they're both adjustable
http://www.head-fi.org/t/526839/dt880-vs-dt990-comparison-review
this is a "decent" comparison between the dt880 and the dt990 (edition 2005 and pro dont make a difference in sound), but the guy is overexaggerating on the treble on the dt990. if you have a chance to try them, you will either hate them or love them