What exactly do you mean by "HiFi listening"? Himedia's DAC converter quality, Signal-To-Noise ratio,...? I do not consider me as high-end audiophile so I could not answer such tech numbers.
However, general guideline would be not to use RCA outputs at all but to send sound in original (digital) form from Himedia player to your AVR which guarantees the best sound for given equipment - I would bet that all decent AVRs does much better DAC then Himedia player. Therefore use either SPDIF or HDMI, whichever your AVR/amplifier is able to use.