Traveling in Bali can be very hard. There is no mass transportation, no street signs and not every one speaks english. A lot of tourist ask should I rent a car in Bali? The flat answer is NO.
The first reason, the streets are completely chaotic and have no real direction.
The second is that not a lot of people speak good enough English to help you out when you are lost. When you get lost you will get an answer that is not right because it is considered rude not to help.