My brother gave me a Black Stone griddle a few years ago. I never used it so I gave it away. Since then, I did buy a stainless griddle insert for my Weber Genesis grill and it has been great.
Normally if I am grilling, I will use the Searwood and my old Genesis grill (not really that old) is solely used as a griddle. I do still have the stainless grill grates under the grill in the cabinet but I just don't use them anymore. To me, this has been the best combo especially since I have both grills but I have heard of people having great success using a griddle insert on their Searwood too. In either of these two scenarios, I don't see the purpose of a Slate griddle nor a Treager griddle.
I'd recommend buying a thick, quality stainless griddle insert on Amazon. Look for comments about rust and if it has any, don't buy that one. I've had my funny named Chinese branded griddle insert on my Weber for quite a while now and there isn't so much as a dot of rust anywhere on it.
