For the money, the Schiit Asgard is such a bargain when paired with the Denon AH-D5000 headphones. If you can get your hands on one, and can deal with the heat and size, you would have to spend a lot more to see any appreciable gains in audio quality.
I love my D5000's, and I use my PC as a source with an optical audio cable (TOSLINK) to my NuForce Icon HDP as a DAC/pre-amp, with the Asgard pulling duty as the headphone amp. The Icon HDP as a DAC is quite the overkill, but the pre-amp voltage output is awesome at (up to) 2.6Vrms, which allows the Schiit to really shine. Using my iPod Touch with LOD straight to the Asgard also produces great results with my D5000's; although, while I might not be able to distinguish between the 2 in an honest ABX double blind listening test, and I'm not certain how I might even do this, I prefer the sound from the NuForce/RCA when compared to the iPod/LOD. (very subjective) That said, a decent source fed into the Asgard, powering a pair of Denon AH-D5000's, sounds fantastic.
If you were in the US, I'd say the price and the warranty of the Schiit is something you should not pass up. However, being in the UK, that might make your decision a bit more complicated. I would be happy to answer any other questions you might have.
