I’ve been using the free Parallels Desktop Lite from the application store. Well its free for Linux and Windows. It also doesn’t do bridging networks - only NAT and host networking. Considering it is an App Store product which should follow the sandboxing rules I suspect its just a fronted for the native hypervisor framework.

I just need to fire an ocasional Linux vem to test something it is more than enough to me. YMMV.