The summer green colour is attractive and the light brown synthetic thatch gives it an additional natural aura.  Success speaks for itself and we can state with confidence that this colour appeals to the largest number of people.  Through the combination of fresh green and olive - coloured blades of grass, the colour is bright but not too conspicuous.  

Do you have no idea which colour of grass you prefer?  In that case, take note of the colour differences in grass in Spring or at the end of Summer.  In Spring its a fresh green, sometimes almost luminous, because the blades of grass are just starting to grow.  In Summer the grass colour moves towards olive green, because its moisuture content decreases.  Your personal preference is the decisive factor here.  You can of course ask for a variety of samples, so that you can make your own comparisons.