Benchmarks of Rosetta 2 emulating x86 on the Apple M1 chip have been revealed, and it looks like it achieves 78%-79% of the performance of native Apple Silicon code.
Although not a strict comparison, the same cannot be said for Windows on ARM when emulating x86 code. One benchmark showed that emulation performed 3x-8x slower than native code.
When we look at what Apple has achieved in preparation for their transition to ARM, one the one hand we see the phenomenal performance of the Apple M1 chip. On the other, we see the amazing performance of Rosetta 2. Although Rosetta 2 is a temporary stopgap solution that may only be supported for a few years, the technology is nonetheless just as impressive as the M1. It is the combination of these two amazing proprietary technologies that will most likely make the transition of MacOS on Intel to ARM nothing like that of Windows.