Really, if we're being fair, a comparison of the two is going to draw parallels -- Regardless of who the bigger star was, both were marquis draws for the company which sent them on parallel courses of success.
For me, Austin's always been more of the "wrestling" draw, since he had an avid passion for the business back then, as did Rock. When he made a media appearance, he usually did something wrestling related, like when he threw Vince in the ocean (river, maybe, forgot the city it took place in). Any of his appearances had something relevant to wrestling, like when he appeared on a talk show, there was one, "Use the words "Vince McMahon" and "Can of whoop ass" in the same sentence".
Rock's appearances were more media oriented. Austin was more symbolic with wrestling because that's where he made his mark. Austin didn't have a legacy of ancestors that made him an instant buzz -- He hit his mark DURING the Attitude Era, and what he was doing then. I'm not saying Rock rode the curt-tails of his relatives by any means. Rocky Johnson, his father, and the High Chief, his grandfather, were well-known wrestling legends, so he had a preset legacy just because of his lineage in the wrestling line. That's why Patterson brought him in. Rock was able to reach out and speak with him personally, since his father KNEW Patterson.
In my eyes, Rock's always been the more media and "crossover" oriented guy. While he did wrestling tidbits in most of his media appearances, he was more 'relative' talking. This is really hard for me to word without stepping on toes, so I'll be as front about it as I can: A lot of Rock's media appearances didn't just focus on wrestling, but his appearances gave off the "movie star" vibe, even if he wasn't one at the time. In mainstream media for the time, you could say Austin was the bigger draw when it came to being focused on wrestling, since he WAS the top-buzz at the time. Rock, however, felt like it was more easy for him to relate on non-wrestling focused stuff, since he had that natural vibe. Austin would do something or discuss a wrestling topic, which Rock did, but he had more 'flexibility', in that he could talk about non-wrestling topics or other areas of discussion. Austin just felt more wrestling-focused on his appearances, for me, anyway.
Again, I'm not knocking either one. Comparing the two, Austin's broken merchandising, box-office wrestling records, and other accomplishments that left Hogan and Flair behind as well, but the Rock did a damn good job of carrying by him.
This debate has gone on since 2002, but really, it's not fair to either performer, since they spoke to two different types of fans. Rock was, in my opinion, superior to Austin in being entertaining on the microphone. Anytime Rock got a microphone, you knew whoever the segment was with, or about, they were going to be destroyed verbally, and you were going to laugh your ass off.
Austin was more of the, "I ain't gonna stand here and make rhymes; I'm going to come up there and whoop your damn ass, son!".
They played off two different sets of fans that, while both men have certain advantages over the other, both were immensely popular. Austin propelled the WWE into the Attitude Era, which earned him a spot. Rock had his own moments, sure, but Austin was the one who pushed the envelope with the material they did, and was the first "mold" to break from the "take your vitamins, say your prayers" stick that WWE had been doing for years, and became the first anti-hero to be that popular. Rock's character that made him popular didn't start emerging until mid-'98, since people hated his babyface persona before the Nation run.
I suppose if you wanted to look at it a certain way -- Austin, and DX, springboard the company into the Attitude Era, while Rock was beginning to find his groove as 'The Rock', but he IMMEDIATELY became a break-out start well into the Attitude Era. Rock became a break-out star during the Attitude Era, which made him a top-guy, but Austin, and to a lesser extent, DX, ushered IN the Attitude Era, which gave Rock the opportunity to become someone who rivaled Austin in popularity.
Had Austin and DX not done that... Rock would have either been in WCW, or somewhere else. I do firmly believe the Rock could replace Austin in being the staple of the Attitude Era, had Austin not become "Stone Cold", but he didn't become "The Rock" until after Wrestlemania XIV. I mean, sure, he did the first-person and he was somewhat with steam in 1997, but he REALLY gained momentum in the summer and autumn after Wrestlemania XIV, which lead to the Survivor Series in '98 which cemented his popularity and capitalized on it. Until '1998, I felt that Rock was beginning to get steam, but he didn't have that "momentum" that he did when they did the switch at Survivor Series, which, as Rock said, "bucked tradition" and made him a sensational hit. After '98, Rock hit heights with Austin, both together and against, financially and drawing-wise.
Rock himself has even said he was the number-two during that period, since he came after the Attitude Era's genesis.
