Pros: Digital Volume Control! size, battery life, sound quality and build quality of course!
Cons: Wow - Pricy!
First - I bought mine used - my complaint on price is based on new price of $400, though I guess it holds value...
OK, that's out of the way. Justin at Headamp builds some of the highest quality hardware I have ever held in my hands - truly beautiful.
Sound quality is outstanding - close to wire with gain as I've heard. I have yet to run the battery down before I get around to a recharge.