I've got an Rx and use it with my DAPs via Line Out to low impedance, high sensitivity IEM when I want a warm, organic yet detailed sound with very precise volume control. The Rx amp section will outperform those of comparably priced DAPs, but you do have to keep in mind the very low output. It can be a godsend when using IEM with ultra low impedance and high sensitivity where the volume steps of smartphones (and some DAPs) can be too large.