The main difference in Micro SD cards, besides price, is the speed of which those more expensive cards can transfer data between your device and computer. I am an amateur photograher and I use the higher end cards in my digital camera and get better quality images with good speed. For my Blackberry, I just want storage space for mainly my music and pictures. The BB is only going to take pictures at a slower speed and I'm not really concerned about quality. If I want to take a really great picture of something, I will use my digital camera. Therefore, I use the cheaper Micro SD cards in my BB. The company PNY makes a really good product for micro SD cards and their website gives some good explanations of the differences in cards.