I was pleasantly surprised at San Antonio's bus system. They were everywhere downtown, frequent, and even had lines that go about an hour out of the city.

I was only there as a tourist though, I don't know how well they'd be for day-to-day life and cross-town trips.

In other cities where I have used buses regularly, I've found them to suffer a bit from limited routes, transfers, it taking 2 hours to get anywhere, and then buses stop running too early at night.