Pros: Affortable, portable, great amp
Cons: Not impressive DAC for desktop
I bought the BitHead as a replacement for my work laptop, where it is a big improvement over the cheap onboard sound card. Trivial to install and sounding very good. Highly recommended for this kind of job.
On my desktop though I get mixed feelings. There I have an Asus D2X and a cheap Behringer HA400 headphone amp. Compared to that the BitHead working as a DAC+amp sounds clearly worse (using Sennheiser IE8 - the cheaper DAC and the noiser USB power is to blame I guess). However, when I connect the BitHead on the D2X directly everything sounds impressively good; it gives additional clarity, soundstage and you will notice new details on favourite songs.
If you are looking for a cheap audiophile soundcard replacement for your desktop, this is not it. You can do better with a D2X or an E-MU 1212M (still far the best sounding source I've owned, Bit-God rest its circuits) - in this range of money.
If you want a sound solution for a work computer or laptop this will be a very good choice.