ThePrimeagen did some benchmarks on stream recently - he found Bun to be slightly better in terms of average response time, but the biggest gain was P99 / P99.9 values under heavy load.

NodeJS seems to drop the ball on a handful of requests when it's getting slammed, i.e. upwards of 10s vs average of 100ms. Bun had a much smaller P50/P99 spread.