Interesting, I've been told just the opposite, that your a fool if you run it at night. Heck, I've been told that you can't leave the water undisturbed for long. And you have to run the pool in several short runs to make up your daily total(2-4 runs of 3-6 hours each).
Like the mods said, it doesn't matter when you run it. Just matters you run it enough to keep your pool looking good.
The factors I'd consider are cost, convenience and comfort, pretty much in that order.
Cost
Do you have tiered electricity pricing? If so you should probably run it when its cheapest.
Convenience
When do you want to test the pool and add chemicals? Regardless of when you do, you'll want the pool to run for a time before you test (30mins or so) and awhile after you add chemical (30mins+)
When do you want to run your pool cleaner? Unless its a robot. You'll want to make sure your pump is running for the number of hours your cleaner needs to clean your pool.
Comfort - (This one is very subjective its almost comes down to personality)
Do you like the idea of the pump running while you ship or not?
Some folks don't like the idea of the pump running while they swim. Others are concerned with possible entrapment issue and don't want the pump running when their kids are in there.
Other still, prefer the jets running while they swim. Since the pump running during or just prior to swimming will blend the water eliminating thermoclines. Some feel the pump running while they swim ensures fresh chlorine is getting everywhere when they swim. This seems especially true of people with SWG's
