Please add Phusion Passenger (https://www.phusionpassenger.com/) to the benchmark for Ruby apps. Right now Unicorn is the only server in that benchmark for Ruby but it's far from the only available server.
However as I explained in https://news.ycombinator.com/item?id=5727232, Unicorn is always supposed to be put behind a reverse proxy. If you do that you should find different results.
Also, there's a lot of tuning in Phusion Passenger that can help performance. The default is optimized for usability and stability. For example if you don't prespawn processes, and let Phusion Passenger spawn them on the first request, you'll be adding tens of seconds to the benchmark time, which would greatly disadvantage Phusion Passenger in an unfair manner. You should set at least:
passenger_min_instances
passenger_max_pool_size
passenger_pre_start