I like to listen to my HD600 using my portable setup with the C&C BH and it works great with plenty of power. I also like the bass boost on the amp with its clean deep sound and the SF switch that gives the soundstage a little bit more air to it. I am looking forward to the Vali when I get it, I just hope the microphonics aren't as bad as the first few batches were.
I've got a Vali, bought it for a giggle because the price was so reasonable I wasn't going to lose my shirt over it. The ringing/microphonics are not so bad at all. The early models had a problem because the tubes have springy wires which are soldered directly to the PCB and the tube is held in place with a sticky soft tape that serves to absorb vibrations. The tension in the springy wires would reduce the effectiveness or the tension would cause the tubes to eventually get loose. They learned to reduce the tension by prebending the leads from the tube. Now the ringing is not that loud and subsides quickly. It works rather well with the HD600's.