I just had lunch at Taqueria Lopez in Durham. I really hope my experience was a gross exception, because that was one of the worst meals I've ever had. First of all, the restaurant itself was filthy - food scraps covering the floor, two flies buzzing around the sickly-looking condiment bar, and the fruit drink containers totally caked with grime. I ended up not dispensing my fruit drink for fear of getting sick. I ordered the quesadilla asada and the tacos campechanas. It took 20 minutes for them to prepare those items, even though I was the only customer waiting for food service.
The asada meat in both the quesadilla and tacos was rock-hard and burnt black beyond recognition. Beef jerky is "melt in your mouth tender" compared to this. Here's a photo:
The chorizo in the tacos was greasy and completely bland. Total polar opposite to the morsels of divine goodness one can get at Los Comales.
Hopefully this was just an off day, but I won't be taking the opportunity to find out.