Heck, I've owned the LCD3, HD800, Stax Omega 2 and the HE-500 aren't exactly blown away by those. It's not the best in all areas (eg: bass texture vs LCD3 or soundstage vs HD800) but it's so good at so many things and has such a nice frequency response (not too dark, not too bright for my taste) that I think it could be endgame for some people.
My only issue with it now after using it for a while is weight. it's not terrible but I just got an old Stax Lambda and the weight and comfort difference is pretty much night and day. makes it harder to go back to the HE500 :(
How would you compare Omega 2 against HE-500?
Omega 2 is a long time desired hp. Always had the feeling it would be my endgame headphone. I really don't see myself upgrading from HE-500 to any other headphone besides it.