I used to like Kong a lot but I noticed that it started under performing when they released version 1. I blogged about that in http://glennengstrand.info/software/performance/springboot/d...
Last August, I tested the Dropwizard service with this setup which recorded about 20,000 RPM on GKE. This year, the same setup sent about 4,000 RPM to the Dropwizard service and the http-log plugin sent only about 200 RPM to the other service.
Definitely something for us to investigate! Thank you for feedback (I'll collect this information to our backlog).