From a controller's viewpoint, we do see RTOs on a more regular basis than you'd expect. However, I've never witnessed one at anywhere near V1 - all the pilot-initiated ones have been from low speed at the start of the roll and seem to be, as power is applied, some sort of configuration warning. Often sorted out after a few minutes at the holding point but occasionally requiring a return to stand.
We're required to carry out a runway inspection after an RTO in case anything has dropped off (unless it is confirmed that it was due to a passenger standing up, or likewise). Not a great issue, apart from the inevitable delays occurring to the queue of departures waiting to get away....