This question What is the quietest range (cooker) hood? is asking for a product recommendation but it is for an appliance. I think this type of question is off topic and should be closed. Recommendations on tools though I think would be on topic. Just wanted to get other opinions before closing it.
I think product recommendations should be allowed for things that are installed permanently. That includes PVC pipe, glue, range hoods, garbage disposals, furnaces, air conditioners, attic fans, sump pumps, electric heaters, locks, walk-in refrigerator parts, and electrical boxes. Here, choosing the right product often has some technical aspects, and it is part of a bigger home improvement project (e.g., redoing the kitchen, running a new circuit to the garbage disposal, or solving the problem of a wet basement).
I could maybe even be convinced that some questions about “loose” appliances like refrigerators, dishwashers, washing machines, and dryers may be on topic, at least if it's about finding a product for a particular situation with unusual requirements. Questions about which refrigerator brands are better built are definitely off topic because it's not something DIYers know more about than other homeowners. I could maybe be convinced that the question asking about quite range hoods falls in this category, but it shouldn't be closed simply because it asks for a product recommendation.