One of the biggest problems with using Canvas to render graphs is the lack of exporting functionality. I built a reporting tool over the summer that used Flot,

One of the biggest problems with using Canvas to render graphs is the lack of exporting functionality. I built a reporting tool over the summer that used Flot, but ended up having to switch it with Google Charts because users couldn't copy/paste results into Word. Image rendering may not be as dynamic as Canvas rendering, but the ability to export images and the widespread browser support still make it a very viable solution