I experimented with the Whonix setup while I was running a Qubes workstation and I was extremely impressed with the architecture. I also read through their wiki and was quite impressed at thorough explanations of the TOR network and opsec in general. I've also read through the actual TOR docs but most of it didn't stick. I see it as more of a reference.
The only reason I ever left Qubes was because Xen still has not implemented a workaround for GPU passthrough with consumer NVIDIA cards like KVM does. I need this for gaming. I now run a KVM system with separate VMs for each domain similarly to Qubes, but the moment GPU passthrough functionality is addressed by Xen I'm moving back.
The KVM experience is quite subpar, for example it is lacking a secure copy-paste between domains and forces me to type out my passwords from my password manager VM when I need them.