Super authentic, super good. I came by at about 9:30 on a Sunday night and only had to wait behind one or two people to order, but as I was waiting for my number to be called the line grew all the way to the back line of the restaurant.
This is a paper plate type operation and I wouldn't have it any other way. If you spend more than $10, I am both really happy for you and honestly surprised. Most things are under $6 so you'd have order multiple items, but they are fairly portioned so I don't think that happens much. If it does though, kudos! I was pretty tempted to hop back in line myself and accept the overeating to try something else - it all looked so good!
There was a also what appeared to be a taco only cart outside. I'm assuming it was for those who wanted their tacos even quicker, but was a little confused because there was no sign or indication of its affiliation (or potential lack there of) with Taco Mich. However, there was a solid line down the sidewalk the whole time we were there for the cart, so whatever they were doing out there must have been working.
If you are visiting GCU or happen to be in the area, I recommend making a stop.