As indicated in the name the Sky Tower has restaurants, a casino, as well as the observation deck from well above anything else in Auckland.
The cost for the elevator to the observation deck is $15NZ ($6US). The tower is 1076 ft. high, the observation deck is circular, is quite roomy and obviously gives you an unmatched view of the city, surrounding islands and ocean. You can stay up as long as you wish and there are snack bars, souvenir shops available to help you spend your money. The ride up (and down) is quick and interesting as glass elevators give you a bit of a thrill ride. It takes 40 seconds to get to the top. There were no waits or linups going up or down.
As is common in other towers in the world there is a revolving restaurant. If you eat there, you reserve at the bottom and then you get a free ride up the elevator. Prices in the restaurant are high compared to elsewhere so one could say you still actually are paying something for the ride. However, on the positive side, we found our meal to be excellent, the service was good, but just slow enough to allow us to spend a full hour (a full rotation) to see all the sites while we ate.
The casino was quite large for those not spoiled by frequent trips to Las Vegas or Atlantic city. Games played are basically the same as those played in Vegas. There are many slots, but not as much variety as in Vegas as about 80% are the newer multiline up to 45 coin varieties that don't really give you time to wish for that last symbol to fall into place. For those who wish to gamble just for fun and pass a little time they have machines betting units of as low as $.02NZ Apparently there is a second floor to the casino for high rollers with dress requirements. In addition to the revolving restaurant at the top there was a cafeteria style restaurant and a couple of other full service restaurants in the building.
Although we didn't stay there, the hotel offered rooms at about $200NZ ($80US) and as the building generally seemed pretty classy, I have no reason to believe the rooms would not be excellent.
The Sky Tower deck is highly recommended to give you an overview of the city and just the experience of being up there. A casino is a casino, if you are looking for one it is there as well.