After a 3 minute walk from the Las Vegas Convention Center monorail station, we found Envy to be quite busy on a Saturday night. Many were dressed rather informally (not us), which was kind of surprising. My boyfriend thought it was because we saw a "Welcome -insert engineering firm here-" sign.
The atmosphere was very calm and friendly. Service was great, I really like how our waitress attentively watched all of her tables in case they needed anything.
We had the signature 19 oz bone in ribeye done "medium-plus" between medium and medium well - because my boyfriend likes it rarer than I do. It was definitely right on the money, but you could really taste the effect of the dry aging on the more rare parts, it was fantastic.
We also had the beef cheeks that had been slow cooked for several hours. The beef cheeks were ridiculously tender, had a pretty thick balsamic vinegar sauce, and tasted better when in the same bite as the truffle mashed potatoes they were served with. This was a good dish to try, but I'd go back for the ribeye. We didn't order any side dishes and were still pleasantly full from 2 entrees.
Oh yeah, don't forget the restaurant.com g/c - we used a $25 one on a Saturday night with no problems.