We ran speed tests with both Crystal Disk Mark and ATTO Disk Benchmark, which are great at showing the transfer rates while transferring multiple files (higher queue depths), like unloading all your pictures for storage or post processing. The sequential tests also help us verify that the transfer rates of the cards are being met, which we would expect of a USB 3.0 device.
Using a Kingston 128GB Class 10 SDXC card we get great performance from both read and write throughput. The Class 10 card is rated for a minimum of 10MB/s transfers and we are seeing upwards of 50MB/s read and about 17.1 MB/s for write for 1 MB file sequential transfers. Read speeds with the USB 3.0 are quick, right around 50 MB/s, which is great and also where having a USB 3.0 over 2.0 is a huge plus; perfect for dumping all your favorite pictures onto your computer that much faster and getting on to more important things.
Write speeds from USB 3.0 are about double that of USB 2.0, which means you will be able to pull files from your computer quite a bit faster if transferring data to your card(s). The USB 3.0 write speed is actually under-utilized because the maximum speed of the SDXC card is much less than USB 3.0 is capable of, but if you are coming from USB 2.0 it will seem like a huge improvement.