For me it's been mostly painless. I've even used Time Machine to migrate from a 2012 Intel iMac to an Apple Silicon Mac Mini and it worked perfectly!

The two pain points:

1. No support for running older virtualized macOS. I like to test back to 10.9 and need an Intel Mac to do that.

2. One Python wheel which doesn't have Apple Silicon builds and doesn't build cleanly: https://github.com/CoolProp/CoolProp/issues/2003