I just happened to stumble upon your post and I actually work for the company who manufactures StoveTop FireStop. Although yes, I'll be the first to admit I might be a bit biased but I can tell you, it's a great product and I have seen them work. Please email me if you want to talk more about it. I can even get you in touch with some property managers who have experiences with them. You can email me at [email protected]. Thanks.
I have seen many communities use this product, and all of them have stated it has at one point saved them from a possible burned unit. However, I have also heard that it has back fired on certain people due to their cooking styles, but overall is a wonderful product.
I think the areas in which you might find this product to be difficult to maintain will be in households where the cooking is mostly frying and/or grilling. Unfortunate a few cultures use high heat to cook certain foods, and they might trigger a negative response from this particular product. My guess, its best to have a response to high cooking, and a bit of clean up aftermath, then actually a fire and then a burned unit at the end.