There are VirtualBox alternatives, but the advantage of VirtualBox is your exported VM appliances may be imported to the same hypervisor on Windows, Mac, FreeBS

There are VirtualBox alternatives, but the advantage of VirtualBox is your exported VM appliances may be imported to the same hypervisor on Windows, Mac, FreeBSD, Solaris, Illumos, and Linux. VirtualBox also has a slicker UI compared with QEMU/KVM on linux & bhyve on FreeBSD/Mac & vmm on OpenBSD. The alternatives all have their own merits, but if people are wondering why anyone would use VirtualBox, I believe the above reasons are why.