I've seen this show twice. The first time around, it was like I was reliving my teens, bopping my head to her best songs and dancing in my seat. I thoroughly enjoyed it.
Second time around, I finally saw the faults in the show and have to give my honest opinion. First off, she probably sings during 10% of the show. There is no big tv screen for you to see her up close (probably because she doesn't want you seeing her lip syncing). If you don't care that she is lip syncing almost the ENTIRE time, you will be okay with the show. The audience in the back get jipped because you can barely see her from that distance.
Also, her dance moves are not up to par with what they used to be and there isn't much audience interaction at all. She talks for a little bit here and there, but it really seemed like she just wanted to get through the show and leave.
This show is the perfect example of Britney as an entertainer and NOT as a real singer. However, even though you won't get live singing during the show, if you are a Britney fan, you will enjoy rocking back to her old hits and reminiscing about what you were doing when that song came out.