Neither man qualifies as either the worst or best, IMHO.
The best? I'd go with Washington. Lincoln, Grant and Theodore Roosevelt are also contenders.
The worst? Andrew Johnson, IMHO.
Andrew Johnson once said this:
I have lived among Negroes, all my life, and I am for this Government with slavery under the Constitution as it is. I am for the Government of my fathers with Negroes, I am for it without Negroes. Before I would see this Government destroyed, I would send every negro back to Africa, disintegrated and blotted out of space.
- Speech in Indianapolis, Indiana (26 February 1863).
And also this, of Frederick Douglas:
- Those damned sons of bitches thought they had me in a trap! I know that damned Douglass; he's just like any nigger, and he would sooner cut a white man's throat than not.
- As quoted in Andrew Johnson: A Profile (1969), "Johnson and the Negro", by Lawanda Cox and John H. Cox; edited by Eric L. McKitrick, Hill & Wang, New York pp. 152-153.
Besides being an unapologetic racist, he was a horrific administer who did everything he could to derail reconstruction....Fortunately, he was thwarted by the Republican majority in the Congress and General of the Army Grant.