In short: everything!
Some will say that there are many devices that do all of this is true, but how many more of such HDMI, RCA (ie the red and white sockets that allow to recover the sound directly to the amplifier without having to go through the TV)? Almost none today. It's a shame to listen to his CD with his obligation to switch TV, or to have the sound on the TV. This is what you will if you do not have a RCA jack like this.
Device high quality! It is a matter