Pros: Nice transparent sound, good build and compact, cheap, opamp rolling
Cons: Tin case looks susceptible to damage, bass boost muddies the sound, picks up interference
Great portable amp for those on a budget. Amp arrived packaged really well and was shipped incredibly quickly to my country. Looking inside the tin, the circuit board and components appears to be constructed to high standards, though the front panel connectors on mine weren't aligned 100% but that is nitpicking.
I use the headphone amplifier with my Samsung Galaxy S at work and it drives my Sennheiser HD580s very nicely indeed! This little CMoy has good soundstage and bass on the default setting and a clean transparent sound. Highly recommended! The bass boost setting however does distort the sound a bit and muddies up the sound somewhat so I seldom use it. The unit also has a tendency to pick up interference from radios and other RF sources. I hope that newer versions might benefit from better shielding to prevent this.
I'm a bit scared that I might damage the casing one day as it looks pretty fragile. To prevent the casing from picking up scratches, I'm carrying the amp in a small sock that I once bought to protect an old ipod with which seems to do the trick. Batteries last surprisingly long, but they are expensive!