The King high flop is not only a safer flop, but it's one in which it will be easier to define your opponent's hand.
With the 7-7-8 and a flush draw present, if someone makes a big bet at the flop you won't know if you have two outs or have the best hand. Plus, even when you do have the best hand you'll lose the pot when your opponent's draw gets there.
The King high flop is one which is much easier to play. If anyone puts in money after that flop, you can be pretty sure he isn't drawing and likely can beat your QQ. It makes for an easy fold.
The 7-7-8 flop is one in which you are actually in no man's land quite often.
