I bought an amplifier for the output fiber of my PS3, playing Rocksmith, the sound was slightly offset via HDMI. Otherwise, I tested it on PC with the L7 ==> good sound compared to the integrated audio output to the motherboard. I also tested my old Cowon X7 ==> good amplifier.
For cons, I still prefer the sound that comes out of my amp "JD LABS C421" but tastes and colors and Prices ...
The tests were carried out with a helmet SEINNHEISER HD 25.