It's hard for me to explain perfectly but I'll try. With the Schiit stack, the sound kind of projectiles into your ear. It doesn't cozy up, exchange pleasantries, and softly seep into your ears. It takes the music with amazing clarity and dynamics, and shoots it out of cannon into your skull. For instance I like to listen before I go to bed. This is not a good idea with the schiit, as they'll keep you up til 3am with adrenaline to spare. For me, I love this quality for 20-30 mins or so, but once you start changes songs/genres it starts to add up and becomes very fatiguing.
Another thing to note is that I'm making these assumptions based on the Gungnir AND Mjolnir. I've heard various accounts that its the Gungnir that brings out the brightness/aggression of the MJ, not the MJ calling the shots. Not sure how much I believe that though..