For me, it's a personal decision. I find BSD more cohesive. That is subjective and has been debated for a decade now. I also find bhyve a bit easier to use, albiet the features are newer and more in number in KVM (for example: bhyve until very recently didn't have VirtIO drivers, so Windows machines would be useless on it).
I'm interested in working in Security myself. Would you be able to tell me a little more about your work? Also, what role/path in security would you recommend for a Cloud admin/System Admin?