Yes, I understand SS is about half what normal carbon steel is - but SS is still about 8 times better than most stone surfaces. If it was just about thermal conductivity then brass is ~ twice as good as carbon steel - so is that better. Energy storage is also important, so density comes into play. That is why aluminum is a bad choice - heat moves fast (maybe too fast) but it will not store enough energy to carry several bakes.
The reason I ask is I have used steel and different stones. Steel sometimes seems too fast for me so I always wonder if falling back to SS might be the sweet spot (SS and Carbon Steel are pretty close from a density perspective) - plus no rust. Anyway, just wondering why TXCraig1 said "Definitely don't get stainless". Maybe it was just cost... No big deal either way, like I mentioned - I was just wondering.