For exact transfer rates I can not say much because I rather am a layman in this respect. But I have transferred about 1 GB / min with a USB card reader and SD Card this. Bin with the speed totally satisfied because I anyway use the card mainly for photos and smaller files.
The printed 64GB have been detected directly from the PC (Win7). And it fits naturally * --- Everything was great even without problems in the MicroSD slot on the Samsung Galaxy S!