We've been using this. It's really nice and straight-forward, although it has some edge cases when you are doing small graphs and responsive layouts. Using it with Angular also adds some complexity.
C3 looked like a dead project about a year or so ago, which I thought was a real shame and planned to move away from it. Just checked the repo a few minutes ago and it looks like things are pretty lively these days. Glad to see it's kicking along again.