Its up to the people to decide but this is for me.
I have finished both games and this is what i say is winner:
Weapons: RFOM (They are all so original it is not funny)
Vehicles: RFOM (GOW you don't use as fun vehicles or as many)
Enimies: Draw (GOW has some totally awesome enemies but Resistance competes evenly)
AI: Draw (In both games the enemies hide, run, shoot and set traps)
Art Direction: RFOM (I think they have better looking landscapes and more buildings ect)
Multiplayer: RFOM (WAR!)
Graphics: GOW (They used smarter techniques, e.g. mostly nightime to cover flaws, also they made verything really shiny)
Overall: RFOM (They havemore original ideas then GOW, and the game goes for much longer)
Watch this http://www.gametrailers.com/vs.php?ep=1&hd=1