You must go into this knowing that this is a Vegas "Show" and not a concert. Brit will not sing, will not engage with the audience and drinks will be crazy.
Our tickets were about $150 and our seats were great. I'm glad that the audience was primarily short females because I was able to take my heels off and still see the stage.
Any seat in this 4,000 seat venue will be a good seat.
Make sure to bring money or pre-game hard. A baby bottle of champagne was $15 and a triple shot frozen margarita was $24 (with a commemorative cup!).
The show starts at 9 but there is about a 20 minute buffer to get people in and allow them to get drinks, there is a large countdown going to let you know when the show is actually going to start.