Fine, let's do this:
By my count - excluding caretakers, and those that had/have less than ten games in charge (seems like a fair cut-off) - we've had 25 full-time managers of Oxford:
Thompson, Turner, Saunders, Summers, Brown, Asprey, Greaves, J.Smith, Evans, Lawrenson, Horton, D.Smith, Shotton, Kemp, Wright, Atkins, Rix, Diaz, Talbot, Patterson, Wilder, Appleton, Clotet, Robinson and Manning.
I'd say that the nine that Mr. Merritt mentions were unequivocally better than KR.
He's then competing in the second tier with Ramon Diaz, Ian Atkins and, yes, probably the Snake. Some really old timers will likely tell me that Harry Thompson should be in that group as well!
So depending on your view, he's historically somewhere between 10th and 14th out of 25 Oxford Managers. Can't get much more bang average mid-table than that!