I compare Iguana Mack's to Dos Gringos because they both offer outdoor gringo-y latin american atmoshpheres.
I used to like Dos Gringos' food better but 'Dos G'" has declined so much in quality. It is overpriced and hardly edible. 'Iguana's food was OK. you know, bar food but I very much like the live music! 'Dos G's' music is basically top 40 over the radio so the music gives 'Iguana' a huge win.
So if you like the outdoor gringo-y latin american atmosphere I would definitely go to Iguana Mack's for the decent food and the live music.