Positives: * Runs with LG G3 (16GB version) so far without errors (2 weeks) * Even when writing quickly the data * The card reader is great - USB 3.0 - also for other microSDXC cards * Speed: * If the card is in the smart phone via USB 2.0 cable from the laptop: 747 MB music files draufkopiert in less than 1 minute * With card reader into the USB 3 port was it (much) faster, but I have not measured.