"Actually HGST was better on average than WD"is probably about the only kind of conclusion you can make. As you have noted, looking at specific models doesn't g

"Actually HGST was better on average than WD"is probably about the only kind of conclusion you can make. As you have noted, looking at specific models doesn't get you anything useful because by the time you have enough data the model is already replaced by a different one - but you can make out trends for manufacturers.