Man this is one of the biggest "it depends" questions ever... I doubt you could really have a definitive answer. Besides choice of yeast strain as mentioned above, it's also going to fall onto what stage the fermentation is in, how quickly it got there, and probably all sorts of other factors.
I think a lot of people vote for consistent temps over lots of variation which made me think of this question: let's say your temp gets out of hand and rises without you knowing. There's got to be a time when it's better to leave it steady where it is, rather than back the temp down. The general rule is that yeast clean up the nonsense they produce during growth and fermentation, so the last thing we want is for them to go dormant while there's still a bunch of junk floating around.
I don't have the answer to that.