I liked the aircraft to fly on but it was pretty uneconomic, driven mostly by the facts that it weighed as much as two 777s when empty and four engines vs. two is only going to have one winner. That and the inability to take much freight with all the passenger luggage filling up the holds and the long turnarounds unless you could put multiple jetties on it.
The people I know that operated it all thought it was great, with good performance (and low reference speeds), an excellent cockpit, nice crew rest and in my airline, decent routes. I never really wanted to fly it though as you got about half the fun things, like takeoff and landing, as there was a lot of heavy crewing, but you got twice the problems, with a cabin crew of 20+ to get through security, immigration, check in, transport, hotel, etc. and all those pax who were going to generate more issues.
They will live on in some shape or form but it did seem to be a gigantic vanity project from the word go. The 747-800 never really went anywhere either so Boeing were probably pretty relieved they didn’t try and build something of equal or greater size...