I concur with twenden on when McAfee releases the daily dat. However, I'm not as concerned with getting the dat immediately, mainly because of the "bad" dats that McAfee releases once or twice a year. I have three Pulls scheduled: one in the early afternoon, one in the late afternoon, and one at 5am. If our network or systems start acting up, I can simply look at the time and know whether or not the daily dat needs to be investigated as the culprit. And, although I'm not here at 5am, I'm not too concerned about it because McAfee does a pretty good job of releasing corrected dats in a timely manner. (In other words, I'm fairly confident a bad dat would be corrected before 5am.)
I guess everyone needs to weigh the risks of a zero day attack vs the potential downtime of a bad dat in their environment. We have enough layers of protection to allow me to be comfortable waiting an hour or two for the daily dat to avoid the occasional bad dat.