Advantages
For personal use a bus is of advantage as it is a cheap service that involves no driving or stress for the person travelling as they don't have to take control of the vehicle. Though the bus is larger there are also many customers paying so the ride cost can be broke down, thereby making the bus ride more inexpensive for each individual
People who ride the bus are also sharing the service and as they are not using separate cars there are less emissions and less of an impact on the atmosphere.
Coaches and buses can also be extremely comfortable and there may be televisions and radios on board. As well as this there is time to read or do work and in this day and age you can even use the internet when travelling.
There is also no need to look for parking places while in a built up area and the bus may let you off nearly exactly where you want to go.
Disadvantages
The bus may be a noisy and uncomfortable ride where you have to share with other strangers; thereby having a lack of privacy.
Buses are also famed for being late and not stopping where you want them to stop. They can also be expensive depending on where you want to go. As well as this the trip may take a longer route than you'd go by private transport.
Buses are also sometimes full meaning you can be left waiting for the next one. They are also less environmentally friendly than a bicycle.
So as is clear to see there are a number of advantages and disadvantages to buses depending on the individual service, where you are and how you want to use them.