The sound quality is a lot better than they make it seem, the marketing shows it being used with PSPs and phones, but they are capable of handling more than angry birds. I use these for PC gaming and music. The sound on these almost compare to my Sony MDR EX700LPs, but with a better soundstage and less bass extension.
I actually prefer these to the A40s, they are much more comfortable, after a while you forget they're there: soft, light, and almost no clamp, it basically just sits on your head. You don't lose much at all in sound quality compared to the A40s, the drivers are only 4mm smaller. The driver in these are 36mm, A40s have 40mm drivers.
I use Hifiman HE 400s now, with an Audio Technica ATR2100 microphone for voice chat.