Comparing to Windows7, Windows 8 has following features System Requirements: Windows 8 works on any PC that works Windows 7, though it may use even fewer resources. Also, it supports ARM system-on-chips and touch-based tablet PC and desktop PC. Hardware support: Windows 8 has built-in support for USB 3.0, many printers, many sensor types, and data modems. Cloud Integration: Log in with your Live ID, and settings, data, and Metro apps sync automatically across cloud services like Microsoft Hotmail, Microsoft Messenger, Facebook, LinkedIn, Twitter, and more. Security: Defender upgraded to fight all malware types. TPM extends to hardware verification and Smart Screen filter enabled throughout the OS. Performance: Performance wise Windows 8 seems to be faster and more efficient than Windows 7. (via)
