I like Race, but the Undertaker is almost the complete wrestler. Sure, he had some bad years early on, but he was a relatively young guy at the time to be put in a WWF main event scene. He was in his late 20's when most of the guys in the main event scene were in their 40's, he really had no one he could be pushed by as he was getting older and better, not until Mick Foley came did the Undertaker truly begin to be good in the ring.
Taker has evolved so much, and I personally think that right now he is better then he ever has been. His inclusion of finishing submission holds to his character are awesome. To see such a long big guy wrap his legs around someones throat is pretty damn impressive. The guy can still go. By this time, Harley Race was having a hard time standing, let alone wrestling. Race is truly one of the all time greats, but the Undertaker is one of a kind.