msi gx70 vs msi gs70

290X is much faster than 765M. So if gaming is your main usage,go with GX70.If you care about portability and battery life,then GS70
 
for some reason I can't select Maziar's answer as the correct one - but it's spot on. GX70 is a hulk of a laptop - but the GS70 is the definition of 17.3' portability.