Anyone know if there is any difference between brands or specs on Micro SD Cards, primarily 16 GB? I have prices anywhere from $30 to over $90, some say same brand name, but I didn't go in and read the specs if there are any. I know on Camera SD cards there are faster and slower cards and that justifies the price difference, but on there Micro SD cards assuming they are all 16 GB, then why such a large price differential?