My local dealer has an assortment of headphones to demo with different amps. They have a 30 day return policy. I bought the Sennheiser HD800. High comfort factor on me, I can wear ‘em all day and don’t tire of the sound. I kept them.
I also wanted some closed back and since the 800’s were so enjoyable, bought some 820’s. They’re a little heavier than the 800’s but it’s not an issue. Same comfort, great sound. I switch back and forth.