I agree that air conditioned buses is something you just can´t expect in Argentina, especially considering many, many places in the city don´t have air conditioning. It truly is a luxury, although many americans take it for granted so much because it´s just simply been there.
I also agree with sergio that something could be done about the noise and pollution produced by the buses, and the problem is something I see very clearly and personally every day. I live on the plaza miserere, aka once, which, conveniently, is the hub of at least 25 bus lines. However, inconveniently, they all pass by my apartment at every hour. I cannot watch TV unless it is on maximum volume. During rush hour I cannot talk on the phone. If you open the window, you cannot even talk to the person sitting next to you. I DO think this is a problem, and it is something that can be reduced. (Particularly because the buses only pass by my apartment because of the Cromañon incident, they cut off the avenue where the bus lines passed, so now they all go down my back street - which is NOT an avenue, and is NOT meant to support this kind of bus traffic.
Anyhow all complaints aside, I have never lived in a big US city so luckily I can´t make these frustating comparisons. I am from Cleveland and in cleveland using the bus is like being on welfare, so for me, this bus system is infinitely better and is very convenient. And you must admit that it is very cheap to travel here. In the US you can spend easily a HUGE chunk of your salary on transport. I spend less than 10% of mine here on transport, and that´s considering that I don´t even work full time. I could never say that when I lived in the US.