I don't believe that K501 have the quality of studio monitors, but it doesn't mean they are bad, especially for USD150, which is silly compared to many headphones, but lets not start this, as we know that K812 are not just another consumer headphones, these are pro gear for studio use and while many already stated that this is marketing only, there are things that changing and many using their PC based systems for pro work to, think of the young and talented guys/girls, who cant effort USD1mln studio, ok?
Personally, I think that this is pretty fair that you compare the headphones based on their price, such as HD800 vs. K812, but their truly goal is way differ and that's what man forget very fast and start the giants war.
Do yourself a favor and just read what cucera wrote, I think the answer is there: extremely precise, dead neutral and absolutely not forgiving. Are these 3 terms are the head ones from general consumer headphones? Don't think so. Just take a look at LCD price range, which in my mind are way over their max, regarding money they are selling for and do you know why? Because nothing of these 3 components are there and that's why it sells so good.
I was bit ignorant, but starting to realize that AKG was and still is not really interesting what general consumer will think of K812 at all. But above all that, I do think that their MSPR is a joke and not the good one either, as the one that should be in the very beginning, was most acceptable, which would be dropping by market itself to around EUR 800, which will be very acceptable for many, but not anymore, because Harman/AKG, most probably, will follow Sennheiser and going to keep their price fixed as well, but we need just wait and see what is going to happened, this is to early to say the last and I think the hype will be over very soon.