Mexican coffee originates from South-central to Southern regions of the country. For that reason, coffees from Coatepec and Veracruz are much different from Oaxacan Plumas, which are in turn much different from the southernmost region of Chiapas. Chiapas borders the Guatemalan coffee growing area of Huehuetenango, and you will find similarities between coffees grown in those regions. In general, you can expect Mexican coffee to be light-bodied and mild, with subtle flavors.
Mexico is one of the larger producers of certified organic coffees, and because of the US close proximity, we receive the majority of fine Mexican coffees in this market. Mexican coffees are worth exploring for the variety of cup characteristics they present, but the bulk of the coffee is poorly picked and processed, so valued flavors are masked by bad flavors from under-ripe coffee cherries and inconsistent processing. There are exceptions, but it seems that the financial rewards are not sufficient to interest estate farms or small cooperative groups to produce higher-quality small lots.
In general, it has become harder for me to find great Mexican coffees from Oaxaca and Chiapas. While other origins have improved their visibility and their specialty coffee production skills, Mexico remains quiet on the subject, having only staged a preliminary auction for quality lots in 2012 that netted very few entrants. Mexico has relied more on the Organic and Fair Trade model to attain better prices, rather than looking for a reward from higher quality coffee. That can work fine, and I support both efforts (as you see on our offer list), but they leave behind those dependent on private farms ... and I believe that part of the market has become more volume oriented.
Mexican coffees are moderately priced, lighter bodied, and wide-ranging in their cup character. For this reason, you need to explore coffee selections from each of the regions to get a good sense of the possibilities of Mexican coffee. Unfortunately, I rarely approve of the cup quality of coffees from Coatepec and Atoyac, and have never carried a Veracruz. Most of the impressive coffees I find are from Oaxaca and Chiapas.
I was in Chiapas for a brief trip which summed up frustrations from trying to work with a cooperative to separate special lots of coffee. Here are some comments and images from this short trip.