I first learned about it while moaning about Incanter in previous Clojure threads! But I don't think it's broad enough (I realise it doesn't aim to be) to usefully capture enough mindshare that Clojure is a first-class citizen in the numerical computing space.
There is no direct replacement, because there are different libraries tackling different aspects of what you may need: high performance computations, data munging, distribution, probability stuff, ML, deep learning etc. Most are on github, some have websites and lists/communities. Google is your friend there. Most of them are still in heavy development, but other than cutting edginess, they do their things much better than incanter would do it (but I never found Incanter useful for beyond helloworld-ish programs even in its glory days so that's not a particularly high bar).
