The number 1 thing that's important about a product is that it works and works well, and this card does.Before purchasing, make sure your phone or camera supports this card. I'm currently using this with the Galaxy S3 and it's been working flawlessly. So far I have only used 16gigs of the sd card and the S3 phone loads everything in a couple of seconds every time I have restarted the phone.Just because the card is class 10 does not mean it will make your device faster. The device being used has to be capable of supporting the card for them to work together harmoniously.Also, some devices (like the Galaxy S3) do not require the card to be formatted and it can be used straight out of the box. With a 59 gig capacity (as the rest is reserved for the card software) I do not have to worry about running out of space anytime soon as I was with my previous 8 gig card.