As business class products become ever more luxurious, is it still worth the upgrade to first class?

What the major airlines have to offer in premium economy.

These are the top airlines in Skytrax's premium economy seats classification that offer them on transpacific flights.

Airline cabin classes like premium economy, business, and first class can be confusing and vary significantly between domestic and international flights. On most U.S. domestic flights, "first class" ...