Chart.js is not being actively developed or patched. Dealbreaker.
I was following several issues that the author wasn't even responding to, even though many people were asking after it. Around 25% of the issues are a year old, and many more are 8+ months old.
Finally, someone made a fork of the project with a lot of the requests that people were making. A "people's fork" wouldn't have been created if it were sufficiently active.