I used Kong in a project recently. Very bare-bones, You need to build your own client for it. Overall, it felt like a blackbox where things magically happened. Totally hated it.
Our official declarative configuration will also be released very soon, and in some environments (like Kubernetes) we already support it.
You can discuss with the community online [1], or meet a core contributor at one of the community meetups or in the monthly community call that we usually announce on Discuss.
[1] https://github.com/Mashape/kong or https://discuss.konghq.com/