I use cast iron on my glass cook top stove, and I too have not had any problems. I just try to be very careful and aware when I am lifting it up or setting it down. So far there are no scratches on the pot or the stove.

I use cast iron on my glass top, and have not had any trouble. I just take care when I set it down and don't slide it around. Glass is higher than iron on the Mohs scale of hardness, so in theory the glass would scratch the iron, not vice versa.

Some people say not, but I've had two glass-top stoves, and I had no problem with my cast iron, even with the uneven surface of a Swedish pancake pan.

Definitely yes if it's enameled. I was extra cautious with the non-enameled type because I was afraid of scratching the surface, but I know others have used regular cast iron with no problem. There's a whole discussion about it in a thread from last year here: http://www.food52.com/foodpickle/2333-what-is-the-best-or-most-go-to-brand-of-cast-iron-skillet-my-mom-has-requested-a-15-inch-one-for-xma