1You play as 4 playable characters instead of 3, and the Baby Mario bros. beat adult Bowser
2Its soundtrack is flawless and much more creative
3Better graphics/engine/visuals
5The levels are much more interesting and graphically perfect.
6It has a more serious, mature soundtrack/content
7It does not overdose on King Bowser
8Not likely to ever be remade (thus a rarity)
9Shroob is better than Dark Bowser
12You only need the stylus once