Ranked in these QuestionsQuestion Ranking
Pros
Pro Multi platform
It is available for multiple platforms.
Pro Customizing
You can theme it the way you like it.
Pro Scrapper included
It includes a scrapper to add artwork and metadata.
Pro Open source
Pro Resource friendly
It uses a simple layout and only a few graphics.
Pro Familiar
It is used in RetroPie, Retroarch, Batocera, Retrobat as launcher.
Cons
Con Hard to configure
You have to edit the XML files to add new systems.
Con Development stalled
However, plenty of actively developed forks exist.