If you create this plan in AWS it's two c3.2xlarge instances with 15GB memory and 8 high performance cores underneath. In GCE it's two n1-highcpu-16 instances, with 14.4GB memory and 16 cores(!). In DigitalOcean this plan is two 32GB instances.
Our own benchmark tests shows that you can reach about 100.000 messages per second throughput with this plan, with one queue, one publisher and one customer.
Please email us at firstname.lastname@example.org if you have any suggestions or feedback.