I should have been a bit more specific: How well do the M-Series run an x86 guest OS?

I've heard not well too. But don't personally know anyone who has experience with this.

This thread, Windows 11 for Arm runs unbelievably fast, seems to say that Windows ARM (not x86) runs well and it emulates x86. One person says well, one person says garbage.

Back to OP's question - I have a two MacBooks and one HP Windows laptop. I much prefer the MacBook hardware, but am 50/50 on the virtue of the OSs. Windows having WSL2 is a big benefit. That said, I'd probably buy another MacBook as they do seem to last a long time, I'm writing this on a 2018 MacBook, and like the Apple integration.

I have an x86 MacBook.

How well do the M-series MacBooks work if you want to run Windows or Linux in a VM?

I'm giving it a shot!

Though right now, I must admit I still haven't wrapped my head around the federates concepts.