I’m in Mexico pretty often. Generally, TJ, Ensenada and Torreon. I’m a partner in a business in Torreon and we’re planning to open a business in TJ before year end.
The violence – as it might pertain to Americans – is overplayed by the media. Yes, you want to be very careful. But, 98% of the violence in Mexico is directed at just a handful of folks:
(1) Drug cartel members and associates, (2) people buying drugs and otherwise in and around the drug trade, (3) Law enforcement (under attack by the first group), (4) the conspicuously wealthy, and (5) politicians and their associates. If you don’t fall into one of these groups the odds of running into trouble in Mexico are very low. Also, as mentioned by other posters, speaking spanish helps a lot if you wind up in a small jam.