Not to mention that (at least compared to the previous release of HighCharts) D3's performance is just so much better. Graphing tens of thousands of data points causes my browser to freeze up for 10+ seconds at a time with HighCharts, while a D3-based graph visualization of the same data loads in under a second.
It doesn't appear to have gotten much better in this version. I took a peek at the new bubble chart (via their link to a jsFiddle) and it took about 7 seconds to render. I'm drawing similar charts using d3 with 800 data points that render in under 300 ms.
That's 7 seconds waiting for JSFiddle, not Highcharts. In my Chrome browser, Highcharts renders 800 bubbles in under 200 ms: http://jsfiddle.net/highcharts/hAyzq/
