The Smith Center is a beautiful location right near downtown Las Vegas next to Discovery kids. This location boasts a large concert hall shaped in a U that hosts broadway plays. This year, my wife and I saw several shows as part of a season ticket series.
We were seated in one of the top box seats on the right side as you face the stage. We also were able to upgrade one day to be seated in the center of the theatre which gave us an opportunity to see and hear a show from a different perspective
In conclusion, the acoustics make it hard to clearly hear the actors/actresses on stage, when singing, the instruments drown out the vocals and they all blur together. When in the center of the theatre, the sound and acoustics were a lot better and you were able to hear what was being said/sung.
My suggestion is not to sit in the upper box seats, thou they are comfortable, make it hard to hear.