But even the objectively superior business class on QR's new planes can't compare with climbing the stairs to the top deck, sitting in 64A [0] with the table and bins next to you for your flight. I first did this in September 2012, on a flight from Moscow to Heathrow. While we were coming in over the North sea I gave the at-seat phone a go -- it still worked (I think they were removed from service a while ago), certainly an experience at the time to be able to talk to someone from mid-air.
My wife and I had a weekend to Seatle in 2014, and bagged seat 1A and 1K at the very nose[1]. I think the 747 is the only plane you can get where you fly in front of the pilot (the A380 cockpit is at the front), and a unique experience.
I wasn't really flying when Concorde was around, and I've always regretted not flying it, but I'm glad I managed to experience both the upper deck and the nosecone on a 747.
(Oh yes, BA's 747 was one of the few planes I've flown on with a window in the toilet)
[0] https://21stcenturyjourneys.files.wordpress.com/2010/09/dsc0...
[1] https://scottmcgee.files.wordpress.com/2010/10/11-ba747-larg...