Disappointed because I usually enjoyed my Kingston products. But this SD card doesn't perform up to specs. It is rated class 4, which means it should be writing at the very least, 4 MB/s. However, the best this card is doing is around 2.5-3.4 MB/s. It only touches 3.4 after a long build up. I have a non class rated Sandisk that is blowing it out of the water at around 5.5 MB/s. This is using the same file, same adapter when testing. The numbers show this during file transfer via Windows 7 AND during a test using H2testw program. After hunting around, it seems that this is an issue that some others have had with Kingston class 4 cards. The speed is important to me since I'm running it in a tablet and it lags when the card is no good.