Ask HN: Which JavaScript DataViz package should we use at my company?

I just got a job as the "rails guy" and "data guy" at a small educational app company. I'm interested in the best/worst, opinions, facts, recommendations, horror stories about JS DataViz packages. Bring it on.

It will be used with mostly vanilla JS, pulling data from an in-house (Rails?) API. My familiarity with dataviz is pretty extensive as far as years, but pretty sparse when it comes to JS. I have 2 degrees in Engineering, but <5 years in Web Dev (and <1 attempting data science). Right now the company/customers are super-impressed with just JQuery's datatables, so the bar isn't super high, but I just want to make sure I'm not "that guy" if I pick the worst thing by accident or something.