LQ, the Tamiya colour is really supposed to represent the post war Dark OD that was painted to US vehicles. This shade of OD was mixed with old oil to thin for painting, hence the darker colour of the base pigment. Tamiya's range is somewhat limited, but naturally they want you to use their colours so recommend them for all OD vehicles.
Model Master is a little bright for my taste, but does represent a good faded colour. My preference is somewhere in between the two (I use Tamiya lightened with a little Yellow and matt earth).
Anyway you look at it, the colour of one vehicle is different to the next one anyway, so go with what you like best.