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 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 Good documentation
Very handy with examples and explanations.
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 Supports multiple Y axes
Important for trend correlation, eg. comparing number of clicks to sale amounts. Not same scales / units.
Tool to easily create beautiful chart from any data then save as image or animated HTML Charts
Pro Can be opened from the browser
The tool is online and can be used from a web browser, no application is needed.
Pro Charts can be exported to multiple formats
Charts can be exported to images or HTML.
Highcharts is not free for commercial projects, with a starting price of US$590 for Single Developer + Maintenance & Support
Con The examples are not that great
For instance, example's JsFiddle may get stalled when loading.