I love Carolina's and have been going there before it expanded to its current size, and every time I go, it's so satisfying! I was even happy when my family moved - we ended up closer to Carolina's. I love the authenticity of the food but the lack of grease. I admit, sometimes I do like that greasy, fatty Mexican style food, but Carolina's is just as good without all that.
I may be a bit boring, but my favorite is the #9 - the two machaca beef tacos plate. it's simple but perfect and always hits the spot. We also love to get tortillas and chorizo and make our own breakfast burritos to take to work or on the go. I also can't get enough of their hotsauce - quite possibly the best thing to come out of a ketchup dispenser since... ketchup.
Be careful when you go. It's the busiest right in the middle of lunch - I've even seen a full fire engine take up the parking lot on their lunch break, and parking is limited. My secret? Call in a to-go order, and beat the long line when you arrive.
While the location may be a bit out of the way, I recommend everyone make the trip just to try it out. This hole-in-the-wall taco joint definitely stands out against other popular stands (I'm looking at you, Filiberto's!!)