Nightly (alpha) build is pretty good (infinitely better than the “stable” build), but I’m not a professional, so I cannot say how good it works with serious projects.

But why only as beer? Doesn’t it seem like a repetition of the Android fiasco if it’s not fully open source?

I am very happy with sc-controller, would 100% recommend trying it out https://github.com/kozec/sc-controller/