Taco Truck - Taikoo place
Coyote - Wanchai
Taco Loco - Central
Taco Truck - Taikoo place
Coyote - Wanchai
Taco Loco - Central
Caramba's is not bad, in my honest opinion. If you are expecting anything like what you might find in the States, or better yet, Mexico, you might have to lower your expectations. I also rate Caramba's as better than Taco Loco, and both are within about 100 meters of each other in Soho.
I have never been to Agave, but I have heard good things about it.