Reaction time allowances are built into V1 calculations. I suppoes, then, the question is whether you are as fast as the calculations assume...
The major ramification of an early V1 call is a higher probability of taking a broke airplane airborne. Since there are few rejected takeoffs within 5 knots of V1 anyhow, the specific probability of this happening to YOU on THIS flight is very low. However, it MAY make the difference in the case where the airborne weather is marginal, especially in the case where you will be forced to go to a distant takeoff alternate instead of simply turning around and landing.
Bottom line: Do what your SOP says to do, and discuss any contingencies or planned deviations in the takeoff briefing.