Comparing two different games on two platforms to determine which platform is better is largely meaningless. There are so many variables that can make a difference such as developer capability and resources, approach, game-style requirements, etc. Also, what looks really incredible to one person might not look as great to the next, depending on personal preferences--some like artistic/manga style graphics, some like depth-of-field effects, some prefer higher photo-realism, etc.
Even comparing the same game on two different consoles isn't terribly reliable as a developer/publisher may have different levels of experience with each platform, or throw more resources at one or the other (I think EA has demonstrated this sufficiently).
In the end, using subjective measurements such as "how good something looks" will never prove anything conclusively regarding system capability or performance.
One final note... while I respect John Carmack a great deal, I wouldn't say he's unbiased. If you've ever heard him give a presentation, then you know the guy definitely has strong opinions.
