Perhaps a non-technical questions but more a matter of opinion, but how far does the sound capability of the RP3 go w.r.t. sound output? I have two larger shelf speakers and an amplifier for about 50 watt. Would you recommend getting the HifiBerry extension or is that only 4 Audiophiles?
Try the standard output, see if you like it. If you don't, get something more expensive.
Beyond that, any reply you'll get will be purely subjective; the objective measurements (SNR, frequency range, etc.) are all available at the respective spec sheets.