There are a bunch of benchmark tests with rainbow under src/arc/lib/bm-tests.arc - I wanted to cover different aspects of the system's performance (error handling and continuations for starters; I'd like to add tests specifically for conditionals, quasiquotes, different kinds of invocations (with/without optionals, destructuring etc)). Rainbow performs better in some cases, and arc3.1 beats rainbow in other cases. I'll have to grab the latest jarc and run a 3-way comparison - more news later!