It's a big, sprawling place--not exactly surrounded by nothingness, but not really an inviting walk between properties either. I have stayed several times at the Palace of the Lost City, which is a big enough destination in its own right. From there you have to take the resort buses/trams to get to the casino, golf courses, etc. I find this whole complex pretty irritating, actually--it's all so incredibly artificial. Night life is just you and a bunch of other tourists, at the casinos and bars. There is no "there" there. If you like big swimming pools, golf, and gambling in a completely purpose-built environment in the middle of nowhere, then by all means...but it is not a destination like Cape Town. (Which I love, BTW.)

The Palace hotel is the best but the prices are fairly astronomical. Service, as in the rest of South Africa, is not at all in line with the prices. This is a great country and a wonderful place to visit overall, but don't expect high-quality service anywhere you go, unfortunately.

The wildlife here is very populous, to the point of feeling like you are on a canned hunt. You will be driving in a bus or Range Rover on paved roads the whole way--no off-road stuff, no hiking. If you have no other game viewing opportunities, then definitely do it, because it will be fun anyway--but you don't get the same experience as you would in one of the wilder, larger game parks.

My very strong vote would be for Cape Town. It is a real city as opposed to a fairly cheesy resort; it is stunningly beautiful; it has vastly better nightlife; you can do interesting outdoor things (Cape of Good Hope); there are great beaches; you can go to the wine country nearby which is an amazing place. Sun City is not Africa, IMO. You might as well be in Florida (except that there is no beach!)