I'm surprised everyone is so quiet about this amp. It sounds great to my ears right out of the box. I'm listening on my LCD-3's.
It is a little bigger and heavier than you would think. I love the red board and 2 internal leds. A poor mans vacuum tube look.
I love the bass. Clearly effortless with tons of headroom. You don't really hear it as much as it's just there, like it's supposed to be. An odd description I suppose. Anyway, very nice.
I haven't had a lot of headphone amps so I don't know that I can give you much of a sound signature or anything. Strangely coming from my Eximus headphone out, I notice the mids the most. Of course, half the time I'm listening to my Pro-900's so don't read too much into that. I give it a thumbs up.