2 BSODs within minutes while now having a total 3 BSODs since installation of Win7 x64 Ultimate years ago.
One shouldn't touch pre-alpha builds being named beta. ;-) And also remember that a DAC is a DAC and a DAP is a DAP so both of them do exist since they are optimized for their specific uses. I wouldn't mind iBasso doing a propper DAC some day, 24/384 or 2x 24/192 but if, then with software like the one for the D7 which runs rock solid.
Firmware 1.5.0 goes in line with the USB-DAC drivers. Since drivers fail, I get warnings about an incompatible USB device each minute if the DX-50 is in USB-Charge-Mode.
Until 1.2.8 it was quite ok, but now they simply tried to add feature which lower the quality since if somethings not there I'll vote that a -0.5, but if something simply fails or errors it's a -1.
Lucky one could downgrade as easy as upgrading.