Tried this on my last trip to Las Vegas. I must say I have a biased to in and out burgers. With that being said I was very impressed with the overall sandwich and shake. I think the thing I enjoy the most about the hamburger was the bun. The fries also are more of a type that I prefer.
I know this is Las Vegas so there is a little bit of a benefit of the doubt but service isn't as prompt or as professional as in and out. In addition, cleanliness was lacking throughout the entire facility. The dining room was a wreck as was the kitchen where you could look back.
I give bun quality to them shake shack over in and out and that is it. Other than that overall value for dollar, taste, cleanliness, promptness to guest and overall customer service I give to in and out.