Highcharts provides 20 different types of [charts](http://www.highcharts.com/docs/chart-and-series-types/chart-types) to choose from, and they make it simple to [combine](http://www.highcharts.com/docs/chart-and-series-types/combining-chart-types) chart types.
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 Excellent browser support
Highcharts supports all modern browsers (including IE6 and up), iOS and Android.
Pro Lots of good examples
The site has a selection of good examples that will help you get started quickly.
Pro Library to support Microsoft .NET
Compatable with .NET framework 4+, can develop graphs from server side for ASP .NETand ASP .NET MVC applications.
Pro Good documentation
Very handy with examples and explanations.
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.
Con The examples are not that great
For instance, example's JsFiddle may get stalled when loading.
Highcharts is not free for commercial projects, with a starting price of US$590 for Single Developer + Maintenance & Support