Buses in any country can be very stuffy when packed with lots of people. Some buses may even suffer from sudden mechanical problems, leaving passengers stranded. But it really doesn't matter what kind of bus system you board because the distances traveled are relatively short. If the bus breaks down, simply get off and find another one. If you plan on staying in a city for more than a few days, and will be using buses to get around, look into purchasing a booklet of bus tickets to save some money.
Site includes routes, prices and photographs from past trips.