I thought this was a sure winner from the average 4.5+ rating with thousands of reviews.  But if you notice the bad reviews involve the card becoming unreliable after a couple weeks of use. Typically people write reviews shortly after receiving the product.  My card worked fine for 2 weeks and then started having problems.  I re-formatted the card, re-inserted in the phone, removed the battery, every trick I could read about but the card still remained unreliable and the phone was thinking it was being removed at random times.  So I stuck my olders, slower 8GB microSD card in, worked fine.I suspect one or both is happening with this card:(a) Some cards are defective but it takes some usage for them to start failing to where the user notices.(b) For some reason, this brand of card doesn't like certain devices, like my Samsung Galaxy S3My guess is I got a lemon, but I'm not chancing it to getting another one and will just move on to another reputable brand."You get what you pay for" may be applicable here.  But a lot of others did have success with this card.  So YMMV.