I have been studying Spanish off and on for many years. Most of the time I have been told 'café' used to translate brown. However, my latest teacher says 'marrón'.
Is one more appropiate in certain situations or countries?
The name of the brown color in Spanish is given by things that have the same color. When roasted, coffee beans have a nice brown color, which gave way to use café as the name of that color in the countries where coffee beans are grown (mostly Hispanic America, as you can see in fedorqui's answer).
Here at the other side of the Atlantic we do not have coffee beans, so we used another thing to refer to the brown color: chestnuts. Chestnuts have a proper brown color so we used to refer to that color as castaño, which comes from Latin castanea and this from Greek κάστανα kástana, so as you can see it is indeed an old word. You can find references to texts such as "un borrico castaño" or "un caballo castaño" in Spanish texts from the XVI century. We still use castaño to refer to the brown color, but mostly to refer to a hair color.
Nonetheless, the most used word here is marrón, which we took from French marron, which also refers to chestnuts. This is a relatively new word. In the Royal Spanish Academy's first dictionary from 1734, the word marron referred to a kind of stone used to play marro, a game. The first time the word marrón was recorded in the Academy's dictionary as the name of the brown color was less than 100 years ago, in 1925, although you can find cases starting from the last quarter of the XIX century:
Of course, once in Spain we were aware of coffee beans and the beverage, we also started to say color de café, you can find texts in publications from Spain starting from the middle of the XVIII century using this expression, and the variation color de café con leche to refer to light brown. Nonetheless in Spain the word café is very seldom used to refer to the color. Of course the opposite is also true, nothing stops people in Hispanic America to use marrón for the color, in fact it seems to be the most used word in some of those countries.
It indeed changes from country to country. In general we can say that:
In any case, there are other words used for this, such as 'castaño' (see What's the difference between 'marrón' and 'castaño'?) or 'carmelita' (in Cuba, as seen ¿Origen de "carmelita" como color? or Bolivia and Chile, according to DAMER's entry).
The Diccionario de americanismos explains in café:
adj. Mx, Gu, Ho, ES, Ni, CR, Pa, Cu, RD, Co, Ec, Pe, Bo, Ch, Py, Ar, Ur. De color café.
That is, that 'café' is an adjective to name the colour and it is used in these countries:
So if we check against the list of countries from Hispanic America we see that it is used in all countries in Hispanic America but Venezuela.