Annihilation.
It was a manageable event, with just the right number of monthly comics to purchase.
It had a tie-in 'Who's Who' in the Nova Corps Files.
It had a one title lead-in with Drax, which gave time to prepare and set up the stage.
It had one spin-off in Nova, which kept the cosmic corner actively in view and held the momentum.
It was the textbook example of how to promote and revive interest in a franchise.