1) Complete package for configuring VM (Virtual Machine)
2) Supports latest list of Operating system to be test in VM.
3) Free and open source
CONS
1) Certain issues of crashes during the installation of OS in vm.
2) Internet connection issues still persist on some machines.
3) Unknown reason of errors when the configuration is done on creating VM, it causes crashes or corrupted.
BOTTOM LINE
Virtualbox is a must virtualization program to test operating system and such premature/mature software with no hassle and complicated configuration to create virtual machine.
Virtualbox is one of the arsenal tool lists of any savvy users to test and conduct a review of any type of software that behaves in a virtual environment.
Personally Me, I love vmware player a lot more then virtualbox because for me it seems a lot more stable. I have been using vmware for a long time. The only time I use virtualbox is when I cant install vmware in a certain linux distro.