I've finally spent a weekend and converted what is now about two years of benchmarking data into gnuplots.

Most recent update two days ago, on the 15th April.

You can now see for yourselves, directly and visually, the variations in performance of each node type across regions and over time - the region wide upgrades (and occasional downgrades).

https://www.redshiftresearchproject.org/cross_region_benchmarks/index.html