The advantages far outweight the disadvantages with one key caveat: If sociopaths control the highest hierarchical level of the system, it will exhibit a lot of unnecessary, destructive malevolence.
I've long thought that autonomous vehicles would become the assassination weapon of choice in societies that have roads, whereas drones would fulfill that interim gap on the path to nanotechnology in undeveloped areas. I just read a novel, DAEMON, by Daniel Suarez (highly recommended!) that portrays this happening as a key plot element.
It's probably no longer cheaper to kill someone with a .50 caliber rifle bullet, even right now. Consider: the cost of the bullet, the rifle, the training, and the increased likelihood of getting caught, and the obviousness that a crime has been committed. However, cars run into cars every day on the highway, and everyone assumes it's just "a fact of life." There are few investigations capable of uncovering murder, especially if the vehicle responsible is not located, or is also apparently destroyed as part of an "accident."
In any case, DAEMON-type cybernetic systems are already ascendant. That's what the current government is: a sociopathic system that maximizes theft.
RE: Dawn of a new age: Autonomous Vehicles