Ranked in these QuestionsQuestion Ranking
Pros
Pro Copyleft
Requires people building on your work to licence it for others to use.
Pro Ensures that the software does not become proprietary
Cons
Con Limits the developer's ability to package or use other libraries/software
Con Copyright
Requires people building on your work to license it the same way you did. Good if you want to pull their code into your project, but issues for potential end users can arise.