This was on our list while visiting Vegas. We were afraid it would be crazy busy, based on the Yelp reviews. When we got there, we were pleasantly surprised. Also, it was a weekday.
There are different lines for different meats. I can see how this could be kind of inconvenient if it's crowded, and especially if you're by yourself and want to taste everything. I suggest going with at least 1 other person so you don't have to wait in all the lines. We had no problem though because it was pretty empty! Once you get all your food, you pay at a separate station.
We ordered 2 carne asada tacos, 2 adobada tacos, and carne asada/adobada fries. All items were delicious. Personally, I enjoyed the adobada meat more than the carne asada. I thought it was tastier and had good flavor. And those fries were not hard to finish at all! :P If I ever come back, I would just get adobada on my fries.
Service was friendly and the place nicely kept. Since they have different lines for the different meats, I would suggest knowing what you want before entering.