Statistically they are balanced out to have no advantage at close or long range. Other factors like abilities or squad plans likely skew this to some degree.
i.e. molotovs are close range weapons whereas rifle-grenades are long range.
I'm a little sad about this The dynamic between volks and rifles in vCoH was for a great part about dancing and softpaddling out if the other had the range/cover advantage. CoH2 doesn't seem to show this awesome cat and mouse game yet