Ranked in these QuestionsQuestion Ranking
Pro Swath of Mario themes from througout the years
From the original Super Mario Bros. to the new New Super Mario Bros the graphics contained in those games is available to use to create any type of level you want.
Pro Use Mario licensed graphics to create your own levels to play in
Mario Maker is about the user creating their own levels of Super Mario through the use of design tools and assets that can be found in a wide array of Super Mario games. This means one can mimic or expand upon ideas found in pretty much any Mario game that exists.
Con Online discovery can be difficult
One can spend hours making a level, to then upload it only to see almost no one play it. The reverse of that is also an issue as browsing for levels is not that intuitive, which makes finding good user made levels to download and play difficult.
Con Levels can be randomly deleted
nintendo has stated that any level that is uploaded online may face deletion if found to be "unpopular" after an amount of time. How much time this is or what specifically "unpopular" means has never been defined by Nintendo, leaving users to see their content deleted at random.