Welcome to the forum. As those who know me will say, it’s no surprise that my vote is for MASSTER. One reason is I was in Germany when it was implemented and actually went to the motor pool, chalked off vehicles and did the paint by number.
But another reason for choosing MASSTER is a bit more practical. MERDC vehicles were almost always painted at a Depot and were spray painted and very professional looking.
Because MASSTER was nearly 100% done by soldiers in the motor pool, and more often than not was applied by hand, you can hand paint the scheme on your model and the rough looking finish with some extra paint in odd places IS a much more accurate representation of how the vehicles actually were.
If you’re interested, you may want to take a look at the series I did from vehicles in my old unit.