I have added a kiln to my studio and bronze clay to my list of materials. LOVE this work, and so far I'm very pleased with the results. The only down-side is the firing time -- either 5 hours or 9 hours PLUS cool down time of at least an hour! SHEESH! But I am cultivating patience, and organizing my work day around the chosen firing schedule.
Of course, before a bronze clay piece goes into the kiln, it needs to be refined as much as possible while still in its leather-hard state -- sanded, holes drilled, cracks filled, etc. Bronze comes out of the kiln incredibly hard, so refining before firing saves a lot of work!