Having compared the M17 and the 320MAX, there really is no comparison. One is good and sounds very decent the other, the MAX is just a few steps (easily) up in sound quality. I have not heard anything that can compare to the 320MAX. Spatial cues, timbre, the sound of a well recorded piano, are all there.
I have also used the line out to the Cayin 300B MKII (with Duelund cast copper caps). The effortless deliver of sound, openness and dynamics comes through with aplomb. I am using some Very fine Ken-Rad 7193s in the Cayin along with either the Western Electric 300Bs or the Elrog ER300B. So either direct out to the SR3, Utopia or Expanse or out of the Cayin, the sound is non stop excellent.
Listening to INXS Let it Ride and literally got goosebumps all over my body, not just my arms. So vast and huge is the sound and transparent. I had to sit back in my chair and just listen. I have work to do so may have to take off the headphones. lol But sound borders on stuff I would not have imagined possible.