You can find a comparison with `bun build` on Bun's homepage. It hasn't been updated in a little while, but I haven't heard that the relative difference between Bun and Rolldown has changed much in the time since (both have gotten faster).

In text form:

Bundling 10,000 React components (Linux x64, Hetzner)

  Bundler                    Version                  Time
  ─────────────────────────────────────────────────────────
  Bun                        v1.3.0               269.1 ms
  Rolldown                   v1.0.0-beta.42       494.9 ms
  esbuild                    v0.25.10             571.9 ms
  Farm                       v1.0.5             1,608.0 ms
  Rspack                     v1.5.8             2,137.0 ms