For my tuppence worth:

US Air business MAN-PHL was nice daytime flight. US Air (domestic) first PHL-SJU was a big comfy seat, poor drinks and food.

United F IAD-BRU was comfortabel lie-flat bed and nice meal. BMI lounge at BRU was pathetic (shortbread and whisky for breakfast!)

Thai 777 F CDG-BKK in the suites was fabulous. Never want to fly another way! Then OK F in standard seat to Sidney. Miracle was that after all that flying, was refreshed and ready to go. Spent the morning sightseeing and then took another flight to Cairns.

Thai 747 in standard F seat that makes a bed was freezing cold, not enough blankets and the maze of heathrow. Never again.

Next flights are BFS -EWR -STT in CO biz. Lie-flat seats. Easy connections, no F available and not worth the detaouyr/miles to upgrade.

So, depends on airline/route/aircraft.

But use TG suites at least once.

Am thinking of Japan to see cherry blossom (ANA) or Dar-es-salaam (LX) just to get a long flight in a suite.