I swapped my miniDSP 2x4 HD for the Flex because of the good results in Audio Scene Review. A direct hit! I was already quite happy with the 2x4 HD, but the Flex is audibly better in terms of dynamic range and SNR. The music sounds even more spacious, precise and clean. The switch was super easy: I just had to update the firmware and PC software, load the preset file from the 2x4 HD and that was it. I can even continue to use my Audiophonics 12V linear power supply. What is annoying, however, and typical for miniDSP, is that the RCA sockets are too close together. This makes cabling tricky, as the plugs touch each other. Thanks to Audiophonics for the super fast delivery.