Guadalajara is a Mexican restaurant with highs and lows aplenty. Our party of six tried a wide variety of dishes - some were great, some were horrible, and none were just OK.
On the positive side the guacamole, nachos, tortilla soup, and tacos were actually fabulous. They also make a tasty Margarita. I have a feeling if you stick to the basics of Americanized Mexican food you will do pretty well. The enchiladas mole was a mixed bag. The tortillas and cheese were perfect but the mole sauce was a waste - no complexity, depth of flavor, or spice - it was just kind of sweet and sickly.
On the negative side the Botana de Carnitas...kind of like pork fajitas...was a complete waste. The meat was dry and fatty and when I asked about the 'two sauces' that came with the dish the waitress looked at me like I had three heads. When I further explained that what the menu said she asked, "So...would you like some hot sauce?" But by far the worst were the seafood dishes. They are to be avoided at all costs.
In summary, pick your dishes with an eye to simplicity and you will do well. Otherwise, be prepared for some unpleasant surprises.