GI called Madworld one of the Wii's best games of 2009. They put Zelda NES as #1 in their top 200 games list. No, they are not biased towards ninty (mostly it's towards the Wii itself.)
The problem with some of their reviews (and other reviewers in general) is that they stick to either only positives or negatives. If one doesn't mention the good points along with the bad or vice versa, that can be considered bias. Anyone who believes a site or mag is more biased than another better have proof or reasons to back it up.