After comparing the HD201 and A500 (both well burned-in) for several hours, I find that I prefer the HD201 overall.
The A500 is (to me) more comfortable, better built, better looking... but the fact is, the HD201 sounds better to me. IMO, the HD201's bass is tighter and less bloated, its midrange is more present and detailed, and it works better with rock. I don't prefer it by a huge margin, but I do prefer it by a significant one.
I'm not saying the HD201 is a superior headphone or anything, I'm just saying that this pair of ears likes them more. Has anyone else compared these directly?