Ranked in these QuestionsQuestion Ranking
Pro Easy to use
Google Charts has a large selection of chart types to get started with and have up in running in very little time. It uses sensible defaults, but has flexible options to allow for customization when needed. Better than most other free to use Chart APIs and has great documentation provided by Google.
Pro Supports multiple Y axes
Important for trend correlation, eg. comparing number of clicks to sale amounts. Not same scales / units.
Con Cannot self-host
Google does not allow you to save or host the code yourself.