I have never done it, but I'm about to turn 64 and I told my Wife "I will never fly Coach again- for International Travel". I used to work in China, a lot, and my job would offer business class for those flights, or you could fly Coach and get a $2,000 bonus. So, I would always fly coach.
My Wife and I flew to Thailand, in Premium Economy, on Singapore Airlines-- that was awesome!!!! On our Return trip to SFO, we were on an Airbus A350ULH. That plane has 4 seats in the back that are SINGLE File on both sides of the plane. WE got two of those. It was epic. The service on Singapore Airlines was unbelievable. When I next fly to Thailand, I will really try to get those seats, otherwise I will pay for Business Class.