Just checked sequential reads with hdparm running on the Nexus 5X:

230MByte/sec from internal flash.
23MByte/sec from the USB stick.

On my main desktop notebook machine:
110MByte/sec from the USB stick, constrained by the PCIe-x1 slot that the USB3 card uses.

And from the Dell X1 notebook (faster USB3 implementation):
120MB/sec read, close to Sony's quoted "up to 130MByte/sec".