We were NOT impressed with Union.
The portions were incredibly small (i.e. we ordered the butternut squash tortellini - $24, it came out with 8 pieces of tortellini) and the service was terrible. I thought it was ironic that our server greeted us with, "Hi, my name is Mike? and I'll be taking care of you tonight".
Our food came out before our drinks did. We saw him walk by our table numerous times, never stopping to ask how our food was or if we needed anything. The bussers and food runners were the only people coming & going from our table and they were not very friendly, either. We actually spent a good portion of our dinner discussing how bad the service really was, sadly. It was almost laughable.
The only reason I didn't give 1 star is because the food wasn't completely awful. I've been to many other fabulous restaurants in Vegas and there are many more I'd like to try. I will not be going back to Union.