The he6 is only useful if you have a powerful amp for it. If you cant listen to it, then why buy it. If you are planning to buy a amp down the road, then it might be a good deal. Otherwise, buy the he500 which people say is pretty easier to drive.
If you have the proper amp the HE6 is worth the premium IMO but I will tell these HE500 are easy to drive and very close to the HE6 and will work a=on most if not all amps. If you have the amp buy the HE6 if you dont want to get a power amp then buy the hE500. I will have my tube amps back this week and will be better able to give more impressions but call me impressed.They do need better pads but sound they are ideal no missing parts here.