Took me ages to find the license, I ended up clicking documentation and still having to search for the word license to find it. I wish it was more prominent on the landing page.
FusionCharts can export charts to PNG, JPG, PDF and SVG. I've been trying both FusionCharts and HighCharts for past few weeks and I can say that I am a bit inclined towards FusionCharts. Had this discussion the other day as well when Epoch[1] was released.
It can be. Therefore it's best to take it with a pinch of salt and decide for yourself. Different requirements will demand for different products. I've seen big enterprises going only for FusionCharts whereas individual developers tend to go for other options like HighCharts. But I took FusionCharts for my personal projects because it was free it had a huge library.
I haven't used d3 but I used chart.js a little while ago. At the time is was relatively simple but lacking some features (like support for interactions). Looks like this newest version has added some of that which is great. My guess is that it's still lighter-weight & simpler than d3 which makes it good for some use cases but not others.
Edit: I've only had good experiences with chart.js (not sure if that was clear)