The one time I saw ball lightning was during a severe thunderstorm. I was looking out of the window, and saw 3 balls of lightning fall somewhat slowly, one of which struck a power transformer. The transformer was fried similar to how it would be with ordinary lightning. The slow speed of the ball lightning was what was most interesting.
The first time was around Orlando Fl around 3 am during a heat lightning type of night. I was driving south and all of a sudden there was something like a magnesium burn floating down from the sky. It burned out in 10 seconds well before it even got to powerline level.
The second time was more dramatic. I was on 595 eastbound around 5pm in fort lauderdale. There was an afternoon summer storm on the edge of erupting. Lightning was everywhere. All of a sudden, what looked like a 3 foot diameter ball of magnesium fire popped up over the highway and just hovered about 50 feet over the ground. It lasted about 10 seconds, but it felt like slow motion. Then, it imploded and disappeared. The rain started a few seconds later.