It's always tough to compare people from different eras. That's like saying Jim Brown was great, but Emmitt Smith was way better because he had more yards in his career. Considering Brown would've had the same advantages as Smith (training, talent around him, facilities, etc.), and considering Brown wasn't chasing a record as those who followed him were, who knows what he could've done? Personally, I think he could've had 20,000 yards rushing in his career if he really wanted to. The guy won 8 rushing titles in 9 seasons and NEVER missed a game!
You could easily compare that situation to Tiger and Nicklaus. Nicklaus would've had the same advantages as Tiger has now, so he may be doing just as well, if not better, than Tiger. Same goes for guys like Ben Hogan, Arnold Palmer, and many others. It does make it fun for discussion, but there's really no telling what peoople from different eras would do were they competing in the same era.