Beijing's subway is a little grimy, the air conditioning is fairly weak, and during rush hours it's like being packed into canned ham.
But it's far superior to the public transportation options in San Francisco and San Jose, the so-called hubs of the tech world.
Unlike in San Francisco, the trains show up on time. Every two to three minutes a new car shows up during rush hours. On a Sunday, you might wait five minutes. It doesn't go everywhere, but the line is being expanded. All the station signs are also in English, and you can get directions in English too.
Public transportation in Asia remains, in my mind, one of the technological wonders of the world. In Japan, the express train ride into town is worth the flight to Tokyo. There's no haggling with the SuperShuttle attendant--you simply buy a $19 ticket and take one of the options leaving every 10 minutes. In town, it takes foreigners about 10 minutes to acclimate to the JR Yamanote line. You see the same thing in South Korea. A cab ride might take 40 minutes, but in a few minutes by train you can get to your destination. Both places also have trains that crisscross the entire city. With global warming increasing, public transportation is going to increase in importance.
Talking on cell phones is also forbidden on public transportation in Beijing, Tokyo and Seoul, something you don't experience in San Francisco. And Americans wonder why we are falling behind.