To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
The first one of these I received stopped working within about 2-3 weeks of having it. Amazon replaced it very efficiently, but then the replacement did the same after another few weeks. I can only presume these came from a faulty batch or something but it's not very good. I was using these in a photo frame (I did wonder whether they were overheating or something but they don't appear to get hot in the frame and I've never had any issues with any other cards in it) but if I'd been using them in my camera I could easily have lost irreplaceable photos if it had happened whilst on a trip or a holiday.