Mocha/chai/(Istanbul|isparta) is my current set up and it's working really well for me. This is for a front project but I'm running the tests on node with Enzyme for my React. It's all ES2015 so mocha runs on the same Babel config I'm using for all my code.
I've heard really cool things about Ava but had some troubles getting it set up with our unique project set up. My next projects will be using Ava hopefully.