You listed the 777 which is an older plane. The newer 787 Dreamliner has been in service for almost 10 years. It is more comfortable because it's composite structure allows for higher humidity and higher air pressure. A normal flight has an air pressure equivalent to being at 8,000 feet altitude. The 787 is equivalent to 6,000. The humidity levels are also higher at 15% vs 4% for other planee. Both of these make you feel less tired and more comfortable.