Well, obviously it's very prescriptive. In theory that should mean it requires less mental effort because it tells you what you should be doing - in practice, I found it required more effort to do things the precise way it wanted. I was far from alone in this belief.

My main issue was with the "related/linkage" stuff (which may or may not have changed somewhat since I was exposed to it), which is unpleasant, to my eyes, in the way it is expressed, and also verbose and often duplicative in what it produces.

A related problem was the Node.js implementation we were using, which generally felt like more of a hindrance than a help (and which we ended up extending beyond all recognition, making matters dramatically worse - though that was no fault of JSON API itself directly, other than by association).

Best of luck!