I currently use it with two limited edition wood headphones, audio technica w3000anv and Denon ah-a100, which I use to drive with the headphone output of my Marantz Reference PM 11S2 and SA11S2.
Compared to S2 I find the power outputs similar but with better dynamics and separation.
Considering the full Marantz system was about 4 to 5 times more I consider the Burson great value.
Regards
Yosapol R