I've also used VMWare products for years; the biggest advantage is that I can run the same VMs (stored on a portable SSD drive) across Mac, Linux, and Windows hosts. Can't do that with Parallels (which I also have but will be dropping once my subscription runs out).
I've tried Virtual Box off and on over the years, but it never quite felt 'finished' to me. On Linux, I think KVM is better anyway, it being a Type 1 Hypervisor.
AIR.