Except maybe members of his staff, I think it's clearly between Sheridan and McPherson.
Didn't Wilson initially come east to run the Bureau of Cavalry, then transferred to a division command?
It's worth noting that Grant's confidence in Sheridan, McPherson, and Wilson was all at least a little misplaced. Not to say they were incompetent. But...
Sheridan was an aggressive fighter, but insubordinate, sometimes reckless, and lacked the temperament to have his cavalry do the crucial work they were needed for because it wasn't glamorous. He's basically the Union equivalent of Joe Wheeler. He was in his element in the Shenandoah and Appomattox Campaigns, but nearly met disaster at Trevelyan Station and left the AOTP blind because wanted to run off and fight Stuart (he exhausted the AOTP's horseflesh in the process, IIRC).
McPherson was unquestionably talented, but he was given a corps command with no prior combat experience (he had been an engineer and staff officer). He was pushed too high too fast and it hurt his performance.
Wilson had a rough 1864, although he had clearly hit his stride by 1865. I think he was a similar situation to McPherson: prodigy who only had staff experience before becoming a cavalry division commander in the largest cavalry corps in the war against some of the best Confederate cavalry. He learned, but he didn't need to be fed into the fire like that.