Depends on the pressure of the area to me. If there is alot of pressure the first week is best, the mature bucks will seek out the nastiest cover and may go nocturnal once they are pressured.
If there is minimal pressure the last week is best as you should have some snow for better glassing and tracking and it may push the deer out of the high country where they are more vulnerable. The pre rut should be beggining also and the big bucks may be getting a liitle stupid,with something other than the survival instinct on their minds.