Very nicely done! I am just about to choose a charting library and this will be a great help.
Have you considered adding some sort of user rating system? I find myself kind of just wanting to know which one is most popular or highest rated (i.e. take some of the work out of choosing between 30+ libraries myself).
IMO rating would be a difficult thing to do as there are many factors[1] to consider. What best for one use case, might be the worst choice for another. A more qualitative comparison would be more useful:
The things that people would most likely vote on are not really relevant. "I successfully made a simple chart based on the examples with this library" -> 5/5. If you need more than the examples, most people will have different backgrounds and requirements. What library they can best use depends on that.
Have you considered adding some sort of user rating system? I find myself kind of just wanting to know which one is most popular or highest rated (i.e. take some of the work out of choosing between 30+ libraries myself).