Hi Rudi,
My M8 is the LX version with RSA balance port. The LX version has an optical input as well as a USB DAC capable of 24/192. It is not meant for iDevices. The optical input will allow you to use the DX100/R10 and AK100/120. I have not heard the non LX version so I cannot comment on the SQ but I was told that the insides of all the Hifi M8s are the same except for the ports. I wished it had a line in/out but I guess we cannot have everything
But I can almost assure you that you will like what is coming out from the M8