First off, a little history on why i got the Valhalla. As some of you may know, I bought a Schiit Lyr last month, and loved it to pieces. Unfortunately, it decided to blow it's brains out shortly after... HOWEVER, I called Jason at Schiit, and he was BEYOND helpful! I shipped the Lyr back the next day (ground), and he sent me a Valhalla that very same day (Fedex 2 day, at no charge). I recieved my Valhalla, well packaged, two days later. And the shipping and price difference was refunded as soon as they received the Lyr. Needless to say I am very impressed with Schiit's customer service.
Now, on to the Valhalla! I pulled it out of the box, stuck the cheesy little rubber feet on the bottom, installed the tubes, plugged in my Sennheiser HD 650's... And I realized why they named it Valhalla. Even before the tubes were broken in, this thing had an amazingly smooth and crystal clear sound! Now that the tubes ARE broken in, I can tell that it doesn't have the raw muscle of the Lyr when it comes to the bass. But the bass is not lacking by ANY means. And I have to say that I like the way the Valhalla handles the bass over the Lyr. Being a tube amp, the Valhalla has a certain... Well, trying to describe "tube sound" is next to impossible. All I can say is that it sounds INCREDIBLE for casual listening, but it wouldn't be my amp of choice for professional mixing. Only for the fact that it hides most of the distorted peaks and background feedback that I can hear through my mixing board and HD 280's.
Overall, this is an amazing all-tube headphone amp for only $350! I would definitely recommend it.
Pro's: Great sound and build quality, 5 year warranty, customer service, made in the U.S.
Con's: Cheesy stick-on rubber feet, I didn't buy one sooner. :P