Physical disk or VHD for Hyper-V R2

Using Hyper-V, what are the pros/cons of using the "Physical Hard Disk" option when adding a drive to a VM as opposed to just creating a fixed-size VHD that is as large as the disk?

The intention is for this disk to be allocated to a single VM so there isn't any requirement to have anything else using it.

Answer

I use VMs because they are portable. When you attach a physical disk, you lose most of the portability. It is much easier to copy a VHD file to another host than it is to move the physical disk between them.