Pros :

• Let you run 2 operating system at ones, this is good for linux user yet can't leave windows because of him/her being a gamer.
• It is forever free and safe for usage since its an open-source program.

Cons :

• I don't see any disadvantage of using Virtual Box unless your using a low spec PC/Laptop It will make your pc/laptop laggy since it consume a lot of RAM and Processor.