I'm not sure I follow -- since Carnival is the "most cruised" line, it means it's the best?
That would be similar to saying that a Ford F150 is superior to a Maserati.
Also, for the site that made the comparison, for being the "#1 most read site for cruising", I have never heard of it.
I do agree that Carnival is a fine line, and you seem to get what you pay for. However, I think (my opinion, which means nothing in the grand scheme of the Earth ) that Princess and (from my research only, not experience) Celebrity far outshine Carnival, but at a higher cost to the traveler.