when u check in at your hotel ask for a copy of the free Whats On Magazine and this is great mag it gives you the low down on everything, times, prices and what its all about.
You can book on your first or 2nd day there, they are very rarely sold out.
Elton John show is good but pricey, we paid for the cheapest seats for Mamma Mia[ booked the day before we went] and showed the maitre'd a $20 dollar bill and he gave us a box to ourselves, we were a party of 3 , we willingly handed over the money, it just depends on what seating is over on the night.
Splash is quite good, but you should read the Whats On reviews and then decide.
Legends is the best impersonator show in town and dont forget to go Downtown and see the free lazer in the sky show.
There is so much to do, you are spoilt for choice. The Latest Cirq is said to be marvellous, but the other are good too, whatever u choose u wont be disappointed.