While I enjoyed Sonic it doesn’t hold a shadow to Mario World.

Let’s put it like this: Sega should have stuck to Alex Kid as their mascot to maybe have a chance to produce a mascot game to rival SMW.

I mean, obviously Super Mario World is the better game, not sure why this is even being asked.... but, personally, I would go with Sonic.

Yeah the gaming landscape at the time also gave Sonic a considerable leg up; in the early 4th generation, the Megadrive had a head start over the SNES and hence a bigger install base at the time both games were new. IIRC there was a brief period in which more American kids recognized Sonic than Mario because of this.

Of course, the SNES ultimately proved to have better legs than the Megadrive and eventually caught up and surpassed it, leading Mario World to sell better by the end of the generation.

This is a bullshit comparison. You are comparing the 4th installment of franchise, 3 installments worth of game design advancements, to the first game in a series that even fans of said series don't go back to. I would have done SMW vs S3&K

Super Mario World, no doubt. Everything from its movement & play control to its level design is top-flight stuff. It's the best platformer of the 16-bit era.

Sonic 1 was a fun game, but it was a bit rough around the edges. Sonic 2 was a big improvement over the original. Something as simple as the addition of the spin dash did a lot to keep its main focus—speed—a continuous thing.

Mario and like others have said, game wise Sonic isn't a real challenger for Mario. I would argue that Rayman games, whilst not as popular as Mario definitely offer a more interesting challenge to Mario game wise.

Rayman Origins and Legends where arguably (imo much) better 2d platformers than SMB Wii and SMB Wii U. Rayman 2 the great escape also really is a classic. In my opinion Rayman did what Sonic never did, which is reach the quality wise heights of Mario platformers. It's a shame the series is dead though, especially since Rayman Legends is one of the best things Ubisoft made in the last ten years.

Personally, I feel the only 2D platformer series that has consistently rivalled Mario's best is Donkey Kong Country.

The NSMB games are merely decent and a lot of rivals can top those, but World and Bros 3 are some of the finest games in their genre to this day.

I mean, I personaly think Sonic games are trash (except for the music). So, Mario World it is.