Josh, steel Plate always wins because the material it's made from doesn't vary. The steel I buy, here in NJ, is going to be the same steel that another member may purchase in New Zealand. Soapstone, on the other hand, varies tremendously. It can be high talc (talc=conductive=good) or it can be low talc (bad). It can have faults running through it that cause it to eventually crack. Mother Nature has horrible quality control.
I got lucky with my soapstone, as have a few others, but just as many haven't been as fortunate.
Soapstone is a gamble, steel isn't.
Your oven is electric, right?