They will work on standard pulse start ballasts if I am not mistaken. The beauty of this bulb is that you can get the great growth that a 10K offers and also the great look that a 20K offers. It is like having two 250 or 400 watt bulbs in the same reflector. It will not generate any more heat than a standard bulb, because only one of the filaments is lit at a time.
Think about it - when you are at work you run the 10K for growth, and then just before you get home it switches to 20K! Not sure how they will compare to other bulbs as far as color and output, but for $100 this is a great idea.
Mike