And you're right to be skeptical. With performance, so much depends on your actual code and program-specific bottlenecks. The difference in runtime speed between JSC and V8 is minimal, so a lot of Bun optimization must be in the gaps between your code and the core JS engine or in startup time (e.g., running `bun install` or `bun test`).

In my benchmarks, our actual runtime performance of long-running JS code is ~25% faster under Bun than under Node. However, sometimes Bun is ~25% slower - notably with tasks that require binary processing (e.g, fflate, sharp) or encryption (e.g., jose). We're committed to JS and will be constrained by its performance for a long time, so a "free" 10-30% speed up at runtime is worth the effort, but it's not a 10x slam dunk like the benchmarks on Bun's homepage imply.