I started out running Windows XP on Parallels. I also set up a couple of Linux VM on Parallels. I no longer have a requirement for Windows, and VirtualBox has become very good at running virtual Linux machines. So I haven't renewed my "subscription" to Parallels. Many Linux distros work just fine right "out of the box" with VBox, including resizable screen.
I started out running Windows XP on Parallels. I also set up a couple of Linux VM on Parallels. I no longer have a requirement for Windows, and VirtualBox has become very good at running virtual Linux machines. So I haven't renewed my "subscription" to Parallels. Many Linux distros work just fine right "out of the box" with VBox, including resizable screen.