You will see the country, and get an opportunity to chat with some nice people.
Mexican buses are generally frequent, efficient, and inexpensive.
They go almost everywhere. Contrary to what some people may think, you don't need to ride with the chickens. The Mexican bus system is far superior to the US bus system. Since fewer people in Mexico have cars, the buses are much more heavily used. This means that many buses are available to most destinations, from third class to luxury.