Although I wouldn't say Chicago has the best dim sum, this tea house in Las Vegas ranks comparable to what I would expect in Chicago's Chinatown restaurants for dim sum.
They bring carts around the table for you to pick the small plates you want and if you don't see what you want after a few carts go by, the wait staff is helpful in getting you your particular choices.
The owner of the restaurant was noted at the time I was dining and helped out as much as he could given that the restaurant was very busy.
We had a wait to get a table, but it wasn't more than 5-10 minutes when I arrived around 12 noon on a Sunday.
I had the traditional shrimp dumplings, pork shui mai, turnip cake, shrimp with rice noodle wrap and all were very good. I will definitely come back to Yum Cha the next time I am in Vegas.