Thinking of getting fostex Hp-A4 to pair w/ denon d5000, anyone have input or personal experience with this amp?

Thinking about buying the yulong d100 mkII (newest version), Matrix M-stage or Burson Audio HA-160 to pair with my Denon AH-D5000. I've been looking for something more out of these cans but since I don't have an endless budget I really haven't had anyway to compare what sounds best to me; but I...