I was in ACA last year and am very comfortable being in Mexico. I've spent probably more than 100 days in Mexico, including numerous trips to Mexico City. I say all that so that I have a little credibility when I tell you that I've never felt nervous as a tourist until I was in ACA.
We saw numerous Mexican Militiamen carrying machine guns walking near the Costera and didn't care for that one bit.
Once one leaves the confines of a great luxury resort, I think ACA has less to offer a discriminating guest than a host of other places. ACA feels a little run down most places and sort of out of control.
Research carefully to determine if ACA is still right for you. It certainly isn't the romantic, idyllic getaway it was in the late 1950s!