In most cases, you will be better off with the cheaper Oppo and use the HDMI connection. Most modern receivers/processors have better setup options than the player will have, and so it will be best to use the receiver/processor for bass management, delays, and level controls for the various channels. As most do these sorts of things in the digital domain, if you used the analog outputs of the player, the receiver/processor would have to reconvert the signal to digital and then after processing convert it back to analog for you to hear. In other words, with most modern gear, you would have an extra conversion back and forth between analog and digital, which isn't going to be improving the sound.
And, of course, many receivers don't do this processing for the multichannel analog inputs, so you would need to use the setup in the player itself, which will likely be more trouble to do and give worse results.
Now, if you have gear that does not have HDMI inputs, and if you are not going to replace it with something modern, and if you want the highest levels of sound quality you can get from your gear (whether the difference will be audible or not), then you might want to go with the more expensive Oppo. But I would advise you to replace your receiver/processor with something more modern instead, and get the cheaper Oppo.
