the worst experiences i've had with public were on the EL or the broad street line. buses, pretty great (except my particular bus was sometimes not on time or just didn't show) trolleys always fine and on time in my experience.

i avoid the underground interchanges whenever possible.

edit: i was in a bad emotional state, but once i sat in a car on the el with one other person, and the car smelled like someone just shit in it. i did this because everyone who came into the car immediately left. i didn't want to be around people. also check the cloth seats before you sit down