My cousin had a rehearsal dinner at Trevi day before the wedding. Our group was seated on one side of the 2nd floor and I think there was about 20-25 of us. On the other side of us, there was a wedding party of 25-30 as well so it worked out well with only 2 groups on the 2nd floor.
We had a 4 course pre-set meal which was, soup, salad, an entree and dessert. The soup was okay but needed more flavor, I forgot the type of salad we had because I was already into by 2nd grey goose and cranberry drink but it was good. For an entree we had 3 pastas to choose from and I choose the Rigatoni Bolognese and was very hearty and delicous. I didn't finish it because it was a lot.
Overall the restaurant ambiance was great and the server kept coming by to refill my grey goose and cranberry. I loved the 2nd floor semi private area, it wasn't too noisy or cramped and had a great time. If I ever get married in Vegas, I'd have my rehearsal dinner or mini wedding reception here.