As always, it depends. Some transit systems are better than others, and some routes are better than others.
I've recently started taking the bus to work and have found that most of the routes keep to their schedule quite well. The local transit system is also rolling out smart bus technology which, among other things, provides real-time location information on each bus. This is available online and through the transit system's app. It's also used by a third-party app, Transit, which is quite good.
Based on my experience, the bus always arrives within a minute of its schedule in the morning. It tends to fall behind near the end of its route in the evening rush hour, though the most I've seen has been 10 minutes (according to the operator's console [when the bus has the smart bus stuff]). This is at the end of a cross-city route, so 10 minutes behind when the bus is passing through at least two construction zones is actually really good.
I should note that the route I take is an express route. I used to take a non-express bus that followed the same path (up to where I got off anyway) and it was a nightmare - usually behind schedule, too many people, too many stops and starts. I decided that the express bus was worth the longer walk.
As for mapping, this is true, but only because there are so many routes relative to rail. Google Maps helps immensely, but it is not perfect.
As for talking to the operator, it's not strictly required, usually you can just deposit your fare in the box and he hands you a ticket. That said, I always thank the operator when I get off. This is the guy that is driving through the traffic so that I don't have to, the least I could do is say thanks. I also make it a point when driving to do what I can to make things easier on the buses, for the same reason.