+1. I've posted on this before. Unusable USB digital input via ASIO from Amplifi75. Windows 8.1, Reaper as the DAW, powerful PC.
USB drive installed, lots of other devices work just fine using their USB drivers incl Zoom G3, Zoom H4N, Novation Xio, ASIO4ALL. And they all worked fine out of the box. Line 6 driver is really poor!