If you're coming from primarily Denons, it's certainly a drastic shift from such a pronounced V curve to a really flat headphone. I was a little apprehensive about getting the MD's because I know I prefer a bit of a V-curve, but Denons were overkill to the point that I couldn't enjoy the mids at all in many songs. Going to the MD's at first I felt like the life was sucked out of my music, I stuck with them for a week, did various Gain/EQ tweaks, and now I can't really go back to Denons. The sub-bass doesn't come close to what the Denons can pump out and rattle your brain with, but I can enjoy every other aspect of the music much more.
The sound is linear, most people have agreed it's a flat headphone, the graphs support this also, you shouldn't really expect otherwise. With some EQ tweaks though they're capable of plenty of punch in the bass (more punch and less bloat than the Denons imo), I say give them a solid listen while you're still in your trial listening period, stay away from your Denons during this time and let your ears adjust. See if the sound grows on you.