So my company (a Symfony shop) is currently migrating its API to this, despite my recommendation, and the lack of maturity of the project really shows sometimes.

So far it has slowed us down more than speed us up, except maybe right at the beginning, which in my experience is usually the case with these kind of tools.

From what I hear there was problems due excessive db queries for serializing entities and stuff. I do not work on that project though so I don't have more details and take all that with a grain of salt.