Generally speaking, a self-drive safari is only advisable if your really know what you're doing. You should be adept at driving a 4x4, and have researched thoroughly how to conduct a safe safari. We think that most people would do better with a guided safari, as you don't have to bother with hiring a vehicle, researching where to find the animals, and so on. Further, a safari driver-guide is well trained in spotting animals and can share fascinating information about what you're seeing.
To help you decide, and learn more on this topic, please read All you need to know to plan an epic Serengeti safari.