Concerning the local Mexican restaurants, in the local Florence, area (with a few exceptions such as Rosies, which some might say is more texmex) most of the Mexican restaurants such as Casa Mexicana, La Hacienda, Fiesta Mexicana etc, get their supplies and food from the same vendor located in Atlanta, Georgia. Pretty much they have similar, if not identical offerings and menus and prepare them in similar ways.
As for the local offerings here I've heard the best, favorable, comments regarding Lahacienda, In the K-Mart center off Cox Creek Parkway, and the Mall Road (Florence) location of Casa Mexicana. That may not be saying much but thought I would pass it along and see if anyone else can confirm that.