Never had a problem with any sd cards prior, and always had a good track record with sandisk products.Card was working great at first, used exclusively in my Samsung galaxy S3. Enjoyed the extra space(got the 32gb card) and transfers were pretty quick. I started to see (about a month ago) that the phone would randomly give me "sd card unexpectedly removed" error maybe once a week. The last 2 weeks, I also started seeing (frequently) "sd card safe to remove" randomly pop up at least once a day as well as the "unexpected" removal error every few days. Today the card stopped reading all together.The card was first inserted w/ the phone off, when I bought it. Although I never formatted it, it worked properly. I also never removed the card from the phone in order to possibly corrupt it from improper removal, so the card just seems to have died of it's own accord. I never thought to check it's temperature after transferring large files so I'm not sure if I had the same issue as another reviewer.Contacted Sandisk, waiting for reply. If they replace the card and it works well, I will revise this review.UPDATE: 2-28-13got a replacement card after about a week and a half, Sandisk supplied a shipping label for me which is always a plus. I've had the replacement in my S3 for 3.5 months now and still going strong. I've also used it with the adapter in my goPro. Card is working well and hopefully it continues to do so. Updated to 4 stars since I haven't had a single problem with this card (the first one started showing issues fairly soon after installing). Maybe there was just a bad batch of the card for spell there.