i think overall holyfield might of had the better overall career cos he was a 2-weight champion & dominated the cruiserweights but in the HW division he won his 4 titles from,, 1st it was a fat unfocused buster douglas, he then lost it to bowe after defending against holmes foreman (who both went the distance with him, holmes had already been destroyed by tyson) he then got revenge on bowe to win back the titles but lost the title to Michael moorer then not long after that gets beat by bowe again
then according to most people he beats a "shot" tyson who hadnt seen his best days in about 8 years (i still give him a hell of a lot of credit 4 this fight cos 2 me tyson was still a dangerous fighter & had that KO power & i respect how evander stood upto him) defends against michael moorer & vaughn bean then he took Lennox the distance earnin a draw then gettin beat in the rematch
after that he lost out on his title fights (WBO against Ibragimov & the NABC larry donald)

im not takin anything away from holyfield 2 b a 4 time heavyweight champion is a fantastic accomplishment but he never really dominated the division & he never held on to a title for more then 3 fights, where tyson had a title reign of 3 years, defended his belts 9 times & dominated the division

so as far as the heavyweight division goes tyson just about takes it in my opinon (close though)