It's funny how those ratings go...
Rift is being given high marks because it's extremely well polished & stable. Trion has made a gorgeous, albeit very derivative game.
Xsyon, on the other hand, is being given marks for potential. No one in their right mind would think to equate this game's state to that of Rift. And yet, I think most people find Xsyon's premise & promises much more appealing.
It's hard to sort through ratings when they're being given for entirely different reasons.