Microsoft have released some updated architecture posters on Hyper-V for server 2012 R2.
This mini poster shows the difference between Basic Session Mode and Enhanced Session Mode.
Enhanced mode provides similar capabilities to remote desktop services with out the need of a network connection to the virtual machine. Point to note: the guest operating system needs to support remote desktop services.
To find out more please see my previous post:
Windows Server 2012 R2 Hyper-V Component Architecture Poster and Hyper-V Mini-Posters
Ryan Mangan's IT Blog 
How do you feel about MS HyperV vs other platforms, such as VMware vsphere?
They all have pros and cons. It all depends on what you are wanting to achieve in terms of product functionality.