> Last I checked Bun still handily beats SWC (and ESBuild) on basically everything

What did you check? Bun only has basic transpiring currently. I can't imagine what "everything" is, and without bundling, minification, and down-transpiling support I don't see how any meaningful project could have been tested on.

> Bun’s perf obsession has been percolating a lot of optimizations upstream to WebKit/JSC

Source? AFAIK claiming either "bun devs made a lot of JSC perf optimization PRs" or "bun devs pointed perf hot spots to JSC devs" would be incorrect, but I'd love to learn otherwise.