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 Supports multiple Y axes
Important for trend correlation, eg. comparing number of clicks to sale amounts. Not same scales / units.
Con The examples are not that great
For instance, example's JsFiddle may get stalled when loading.