A320 Left seat
A very interesting question, here is my take.
As stated earlier, up to 100kts on the A320 is considered "low speed" for a RTO. (It was 80kts from memory on the 787)
On take off, I attempt to quickly scan left to right across the cockpit as we approach the "100kt" call, this takes in My PFD/ND, ISIS, EWD, RH PFD/ND. My theory is I will be aware of any issues with Airspeed discrepancies, failures etc prior to the "High Speed Regime" starting. (this is made more difficult in high crosswind, 30m Rwy or LVP conditions)
Hopefully if I was faced with this failure, I would have enough SA to either STOP or GO in a timely fashion regardless of whether I was PF or PM.
If the F/O is PF, the startle factor and the ability to get a clear message out will be the hardest part.
But that's what we get paid the big bucks for.