Something more on Bus Travel in Mexico

Between Dec 18 and Dec 29, 2009 we took busses in Mexico between:
Zacatecas and Mexico City
Mexico City and Oaxaca
Oaxaca and Huatulco
Huatulco and Mexico City
Mexico City and Zacatecas

Overall, travel was comfortable (we were able to sleep when we wanted,) but even though all buses were described as First Class, we encountered 3 different categories of service.

One, used a bus with only 24 seats and included a "lunch/snack" plus soft drink and you could ask for Nescafe packets to make your own coffee from the hot and cold drinking water aboard. Tea bags (lemon) and sugar were available.

Another, used 32 passenger busses and only provided a soft drink. There was hot and cold drinking water and tea bags.

The last, used 44 passenger busses (only 3 less than Greyhound) and there was no drinking water on board.

Legroom and in one case seat width varied from ample too slightly better than Greyhound. All were considerably more comfortable than Greyhound. On time performance is better than the airlines and bus travel is a good first choice if your not in so much of a hurry you have to fly.

I have read where it is not really necessary to buy tickets in advance. That's true with significant exceptions. If you need to be in a certain city on a certain day and are travelling during peak periods, it's best to buy tickets at the time you make hotel reservations. The hotel can probably guide you to the websites for the bus companies that can take you all the way from the US border to your destination. Unfortunately, there is not one stop shopping site for all bus lines.