I did at the start but that was more user error than the board tbh. Usually when flashing the bios i do so under ezflash within bios from a usb drive. But for the Devils canyon bios, you have to use the asus update tool in windows. This can be downloaded along with the most current 1505 bios, (released yesterday) 1504 beta came out several weks ago.
No idea either on the release of the Z97 formula, but if you later intend to move to a broadwell cpu, you will need the Z97 board, as its rumoured that the DC chips will be the last on 1150 to be compatible with Z87.