LuckyDay has hit the high points.
D-day is the weakest version but it is also the fastest once you get the turn sequence down should get most games in under 2-1/2 hours and if you want to have beers while playing the most forgiving to less than complete focus.
GCNL is a bit longer but it can FEEL faster with alternating movement of each units (1st player moves TRNS, next player moves TRNS, then BBs and so on) and keeps you involved cause you don’t really have your turn/opponents turn.
GCNL has much more in the naval and logistics departments and a random casualty system.
Poke around the boards there are many threads on this version vs. that version.