I used this marinade for beef, pork and chicken fajitas a couple weeks ago - cooked for 20 people. For the chicken, we just replaced some of the soy with a teriyaki sauce (Kikkoman brand, same as soy). I found that somewhere on the Internet that someone said they thought that was what Pappasitos did.
Anyway, it came out awesome. I bought HEB sirloin skirt steak (butcher said it was the best they had) and for the pork I just bought sirloin pork chops and cooked them. The pork disappeared. For the chicken, boneless skinless thighs. Put them all in bags of marinade in the morning and flipped them around to redistribute the marinade a couple times, then cooked them at supper time.
They came out really well, and I will DEFINITELY use the recipe from now on.
One more thing - don't forget to get GOOD tortillas. I get mine from the local hole-in-the-wall Mexican restaurant. Great fajitas need great tortillas.