Comparison between the approaches
Among the first three approaches, the Unix solution is the simplest of all because as long as we have created a page that can export Highcharts graphs, we can apply it straight to the server side; there is no need to write new code. Another major advantage is that this approach is not restricted to any particular version of Highcharts; what works on the client side is mirrored on the server side. We can plug in the latest release of Highcharts and still it works perfectly fine. However, the only downside of this approach is that it's only available on Unix platforms.
Both Highcharts' server-side Export (HSE) and Node-Highcharts solutions embed with specific version of Highcharts, which may require the updating of the package as well. At the time of writing, Node-Highcharts is internally embedded with Highcharts 2.0.5, whereas HSE is embedded with version 2.1.4. Another slight disadvantage with these two techniques is that there is no direct access to the...