I found the buses in Beijing to be "good public transport" as long as a) you could do the entire journey on one bus, or one transfer where a lot of buses could be used to get to your destination, b) the beginning stop was close to your location and the ending stop was close to your destination, and c) both stops were served by multiple lines. Given that buses in Beijing are spaced an average of about 10 min apart, C means that you didn't have to wait long for the bus. The subway travels faster, but you typically have to walk ten minutes on either end, so the bus will win. I frequently used the bus on routes that satisfied all conditions.
The down side is that you need to be familiar with Chinese characters, and do a lot of clicking and zooming in and out at ditu.google.cn beforehand.
