Holstein's is located on the food level (2) of the Cosmopolitan hotel on the Las Vegas strip. When we went Saturday evening, it was crowded but not terribly so. You have the option of sitting at the bar or waiting for a spot. Since the bar was full, we went onto the list. I liked that they text your mobile phone when your table is ready. This allowed us to walk around and take in the sights of the hotel a little bit.
I ordered the Rising Sun burger along with a Hoppy Lager (on tap) from Sierra Nevada. The burger was delicious. The lager was pretty decent too - they did seem to run out of some other SN options early, though - my previous 2 beer selections were both sold out.
In any event, I enjoyed the meal. My wife ordered the Ahi Tostados, a decent and interesting dish. We also shared the Truffle Lobster Mac&Cheese, which was exquisite.
All in all, the total came to about $60 - hey, what do you expect when you're on the strip? Worth the trip if you are in Vegas and don't want to get too fancy. Yes, it's pricey, but so is everything else.