We have all played Mario, He after all is the subject of some amazing games. Sonic on the other hand has gotten bad games like Rise of Lyric and Sonic 06,a game so famous for being one of the worst games of all time. Sonic has been the subject of a couple good games but the number of functional games without glitches that break the game to your favor or to the games makes it clear that Mario is indeed better. Ask anyone who Mario is most people will know. Also the Sonic games lie to you Sonic is not the fastest thing alive. Mario is the far superior game
However Sonic games have much more creative story lines compared to 'Saving the Princess' in the majority of Mario Games. Also Sonic saves entire world over one princess meaning through out all the games he has saved multiple lives with multiple lives. Whereas Mario has saved very few.
In Sonic's games there is usually more story plot and side characters which the player can take the roll of for certain task. This makes each game more unique rather than the repetitive story plots of the Mario game.
The other side brings up story, however what good is story when your games are full of glitches, and certain characters have an annoying effect on the game. Take the player two for example Tails is a bratty kid while Luigi is Mario's little brother. If you want to talk story the maker of Sonic himself said he ripped of Dragon Ball Z. Mario games are not plot centric making more focus on game play witch is the most important aspect of a video game.
However Luigi is a very similar character to Mario with the same power-ups and abilities as Mario. The difference between the two is only height and the colour of their clothing, along with minor facial details. However Tails is a completely different character with the ability to fly or hover (depending on the game). He also has a complete different appearance to the other characters. The opposing side mentioned 'glitches' however you will find every game including the Mario games have a fair share of glitches. They also mentioned game play being more important than the story line however this is an opinion as many people believe the story plot is just as important if not more.