Our friends at GamersInfo.net say this:
No game shall be compared to another game unless it is a sequel. All games should be reviewed on their OWN merits or you run the risk of the player not understanding the comparison.
You may notice that I work on more or less the opposite philosophy. I see everything in a web, with connections to all the other places from which this game got its ideas. I might throw in some books and movies too. I am also quite happy to label a game as “[existing game] +/- 5%.” Because if you are not going to innovate, I am not going to pretend you started with a blank page. If you already know the industry standards, saying how this game differs slightly is how I will express myself most clearly. If you do not know the industry standards, you are probably not reading a MMO blog.
But we love our friends at GamersInfo.net and wish them well on their approach to things. We are just not that kind of site.