A brief note on performance: Ur/web has been in recent rounds of our project and has performed exceptionally well. For instance, achieving 112,807 Fortunes responses per second on our Peak Hosting hardware:

http://www.techempower.com/benchmarks/#section=data-r9&hw=pe...

And the code for the same:

https://github.com/TechEmpower/FrameworkBenchmarks/blob/mast...