It can depend on where you're hunting. If hunting suburbs, human pressure may be too much for anything but the common "dawn/dusk" times.
But if one is looking to fill a buck tag in the more typical rural setting, when the chasing starts, mid-day can be king. Most does are bedded up by 10am and the bucks are still on the move, looking.
Mid-day during the rut is a good time to do some aggressive grunt calling.
For me personally, my 2 best bow bucks were both taken around 3pm and the 2 nicest bucks I've seen in a few years were ones I grunted in around 3pm, but he busted me due to sloppiness on my part and the other was about 10:30am that I grunted in to about 8 yards but sadly had no shot due to him facing me head on in thick 2nd cut poplar.
I know folks love to get up before daylight and watch the woods come alive and that's the smart tactic in early season, but during the rut, I've better success going out around 8:30-9ish and staying out as long as possible.
If you do go out before daylight, and the rut is in full swing in your area, don't believe for a second that when 10am comes around, that the hunt is somehow over. In many cases, it's just starting, if a buck is what you're after.