I got to hear them last week; they are very well balanced --- and probably one of the least bass-heavy Monsters I've heard! I'd say it's as close to neutral in tonality as Monster will ever get (as of now).
I'm a little disappointed with the materials they used, though. It's noticeably plasticky, though they have a collection of really unique gel Supertips shaped just for the Gratitudes (and color-matched too!)
The housings didn't seem plastic to me (it had a nice heft to it)... The rest was plastic, but still felt fine to me.