Bun 1.4.3 says `bun check` is 3x to 6.4x faster than tsc 7, and on three real repos we measured 2.6x, 2.9x and 4.4x, so the low end of the claim does not hold everywhere.
`bun check` printed exactly the same errors as tsc 7.0.2 on all three repos, with no differences in the sorted error lists.
A warm incremental `tsc 7` run on our Next.js app took 0.20 seconds against 0.22 for a cold `bun check`, so a CI job with a cache gains little from switching.