Something must be draining the battery.
Mine is much better than I would expect. After a full day of heavy use (2-3 hours of gaming, 2.5 hours of movie streaming, several hour's web browsing, 100% brightness, turns nothing off), still 20%...
p.s there is an update being pushed out today, maybe it will help...
KB 2756872 Improvements
This cumulative update includes the following performance and reliability improvements:
?Increased power efficiency to extend battery life
?Performance improvements in Windows 8 applications and Start screen
?Improved audio and video playback in many scenarios
?Improved application and driver compatibility with Windows 8