Having survived this atrocious service for some time of my life, I think it is fair to say that this is one of the worst transport systems any metropolitans can have.
Second only to the Water-lorries and the metro intended potholes in population control, this is a highly efficient population control mechanism. There are many drivers (if you take a percentage), who are so frustrated with wages and the crowds along with air conditioned weather (!!) of chennai to aid their fury.
They do have many connections and some-times you may end-up spending couple or three hours before catching your rides.
They are also very helpful in giving you your mandatory exercise by stopping few hundred yards away from the bus-stop.
You also have the privilege of all or none ( no bus for 2 hours and 5-10 buses together in few minutes) policy. How graceful.
Sometimes it is better to walk or pay the money to an auto-wallah thane go in a bus.
Due to the crowd, it is better to be avoided, especially if you are a girl, unless you want to be mashed liked a potato by some friendly rougues ever-present.
Only thing is the cost of transportation which is quite OK.
Avoid it.