Windows8 is just the upgrade of Windows7,well i ve not used it much but Graphics And visuals are the best features i believe.
best features of Windows 8 1.Can run on Intel or ARM devices. So far, Windows has only been supported by Intel chipsets. 2.An OS for all devices - PC's, netbooks, tablets and smart phones, whatever be their screen size. 3.Less demanding of hardware resources than Windows 7, barely so, but still creditably enough. As a result, it can run on netbooks powered by early Atom processors with 1 Gb RAM. 4.Boots up in 8 secs.
I love how it won't run Silverlight so all the Silverlight developers are out of a job. You gotta love how Microsoft just dumps on people. Never, EVER trust Microsoft.
There are many tweaks and changes in Windows Server 8. There is increasing network performance and management, Active Directory repair, repair handling data storage, improved virtualization and more.