First off saying Austin is the greatest wrestler ever is laughable. The guy was great and was really popular for a couple of years but come on dude, to put him over HBK, Flair, and Hogan is nonsense.They seem inseparable but there is a way to determine which one is the winner in the end.
Both Shawn Michaels and The Rock had careers that overlapped the career of the greatest wrestler ever to walk the earth who I don't even need to name in this post because everyone knows who it is, so lets see how they went against him and how popular their feuds were.
The Rock wrestled him 3 times was pinned clean once by him but defeated him twice, once cleanly and once with blatant disregard for the rules.
The Rock's feud with the greatest wrestler of all time was epic and even though his opponent ended up with a moral victory and gained most of his fans back who had lost their way over the years, the rock still won the match so thats a huge star against the rocks name.
Undoubtedly the biggest scalp of the rocks career and their first match headlined wrestlemania even though it wasn't the final match on the card.
Shawn Michaels turned to the only wrestler he thought was worthy of teaming with in a time when Michaels and Hunter Hearst Helmsley were not on the same page. He said if he could have anyone as a tag team partner he would team with the greatest of all time.
Shawn Michaels turned on the greatest of all time and challenged him to a match, hoping to take the biggest scalp in wrestling and have a hugely popular feud. The match was so anticipated, that it actually pushed both world title matches to the undercard.
Shawn Michaels was defeated.
So in conclusion The Rock will have the bigger place in wwe history as he measured up to and beyond the greatest of greatness, truly earning the title of "the great one".
The answer to this depends on who you ask and what you mean by better. If you ask hardcore wrestling fans they will say HBK but if you ask the rest of the world they will probably say the rock. I believe that HBK is the best ever so there's my answer right there. HBK, as far as matches go, cant be touched but the rock, as far as promos and entertainment, cant be touched. Both have done an awesome job for the WWE and are among the greatest of all time.