Overall, the experience is exactly that. A bus ride.
You run into crazies, overhear crazier conversation and start to think crazy things. But hell, I don't have a car so I enjoy the ride and observe the people and learn to plug my nose.
Generally, the bus drivers are great, friendly and polite. I don't want to say there are no cracks in the egg though, so I just grin and bear it.
But be warned, if you're a fraction of a second late - the bus will leave without you despite how close you are to the door (for the majority of the time). Lots of routes are being cut/eliminated/reduced, so plan for more time in your schedule.
What gets me going are the people that try to jump on without fare and the bus driver kicks them off or the metro police do the same.
Just don't sit where the wheelchairs are placed, if at all avoidable. More than likely you'll have to move and just may lose a place to sit. Take a supply of an anti-bacterial product with you so you don't leave the bus with pnemonia or mrsa or worse. Bring headphones to drown out the noise of screaming babies and get a laugh at the expense of others.