Product review (3 stars): So far so good, but..
Have only used it one day, so can't speak to how well it works. But the filter bows upward when the range hood fan is on (due to upward air intake), causing the mesh to bump into the fan. Not enough clearance. A simple strip of aluminum across the center would prevent this - though it might also interfere with fan. (I am using this with a new Broan QML30 under-cabinet ductless range hood). Not sure if the problem is that the filter bows too easily, or fan is set too low on range hood. Stiffer aluminum on the charcoal side of the filter might fix it. For now, I've rigged it so that it rests on supports against the back wall (vs. in metal slots in range hood), which provides just enough room for fan to spin freely.