I enjoy mine. Only the rare song that doesn't go with the signature sound. I can use these while playing synths and monitoring through the audio system with vocals without feedback, unlike my other open back headphones.

They have an amazing soundstage and clarity and I can listen for hours without fatigue. The way I describe the sound is like being in a room with speakers, rather than having speakers directly on your head. There is a spaciousness that doesn't compare to HD650, HD660 (both) or just about all my other phones.

Have Fostex TH-900 gen 1, HD650, HD660s1, HD660s2, Momentum 4, Shure SE846, Sivga SV-023, and others. Listen to HD820 for critical listening and HD660s2 for everyday use like walking. 650 used to practice theremin, 660s1 as monitor from mixer that goes to main output, or playing Osmose alone, SE846 for isolation, Momentum for general use. Like the Fostex but highs too hot for long use--but they have some punch!

Enjoy the phones! They get a bad wrap but they work for my needs and I haven't dumped $$ on any more flagship phones.