I avoid it. I try to get everything I can from the mix and leave the master EQ to the mastering engineer. Having said that, if there are things you find yourself frequently doing to all tracks it may be worth putting a slight curve on the end. Some guys mix with a low or high end bump, but quite honestly I wouldn't be doing anything surgical nor even remotely as drastic as 5-6dB gains/cuts. My GSSL appears to bump the highs a bit with its light saturation, but beyond that I haven't used any master bus EQ at all on my latest work. It's all left to the ME.