'What is it about New Super Mario Bros. 2 that makes it such an exception?'

It´s a 2D Mario.

It beeing very well advertised thats for sure.

Also its turning out to be the fastest title to reach 1 million sales on the 3DS. Some sony fans on this website will try to tell you that 2D mario is on decline, but it really isnt that simple since the 3DS has a smaller userbase than the DS and Wii had by the time their versions released (besides the fact the portable gaming market has been affected by the phone market).

To answer your question, the difference is that it's the 2D Mario series and people from the opposing camps know how powerful of a franchise this is with consumers. Even more powerful than the 3D Mario series, so they take every opportunity to diss it .

I, being that I am a curmudgeonly old duffer, still need to get this game but have had trouble leaving the house because of my aging old bones. Also, I don't know what downloading is and don't want my identity stolen so I won't get this game that way either.

Swallow your pride and admit what you've been trying to deny for ages.... quality wise 3D Mario>>2D Mario

Mario sunshine is still my favorite Mario game... i dont know what people though was so bad with it. I loved the graphics and water mechanics with the HUD device.

3D land looks interesting aswell, but it didnt have that WoW effect that leads me to buy a game.

Incidently, sunshine was the only mario game i ever bought (though not the only one i ever played).

It's more popular and more "simple" so easy to gain views on gaming media. And wouldnt be the first time they do it. For a compnay as old as Nintendo they sometimes are looked with very high standards, and that's fine considering their time and experience, but they sometimes want new or old concepts, never both of them.
Also the broadappeal of it makes it very hard to have a concensus over the quality of the title between the players. Popular Ninty games have the most mixed opinions in my...opinion.
I usually ignopre the scores tought and just read the review.

Have you played GTA 4?  It's the greatest game of all time.  The reviewers said so and I always trust the reviewers.

I love you Rol. Never stop thinking.

Your binary way of calculating scores and similarities does not reflect the true nature of the world with its continuous variables.

Nice table I haven't played it yet but from everyone I know who has it they love it so that's enough for me to pick it up. though I was gonna get it regardless.