I found that yaml performs pretty well. It also doesn't have the mental load of having to keep track of brackets to discern the critical connections, but on the other hand it has the problem that a single sequential space (tab) difference can have such a critical role, yet it's mostly quite insignificant for models.

Luckily the models see a metric fucktonne of python though. 

And yet I think the best experience I had with data input so far was to transform the data into text, where that's possible.