Many years ago, I tried Parallel. Not so much like it. One thing is it is not free. Now, VirtualBox has become my favorite software which must be installed on any new PC (which support virtualization). So whenever I look for new machine, I will always look for one with i7 CPU and a lot of RAM. So I bought the MacBook Pro with i7 instead of the cheaper MacBook Air.
I used to run macOS as guest OS in Windows 7/10 host (to work with B4i). From Lion until current Catalina. Haven’t tried with Big Sur. I can run iPhone simulator inside the guest.
Now, I am running a Windows 10 as guest in macOS host (to work with B4i, B4A, B4J). One thing I miss now is how I am going to run Android Emulator inside Windows guest?