Ideally, you want to do both, especially if your Bluray player internally decodes the new hi rez codecs available on Bluray,that being Dolby True HD, and DTS Master Audio.There are still very few pre/pros on the market that can receive and decode these new codecs in the digital domain, so the only way to take advantage of their superior sound quality is through discrete 5.1 or 7.1 analogue outputs of your Bluray player to the multi-channel analogue pass through inputs on your pre/pro. The same will go for SACD, or DVD-Audio if you choose to utilize these formats. Even the uncompressed PCM multi-channel soundtracks that are on some of the early Bluray discs will need to be output through the multi-channel analogue connections. As far as standard Dolby Digital, or DTS soundtracks on regular DVD or Bluray discs then yes a digital coax connection is probably the best way to go. Surprisingly there are still relatively few Bluray players that are fully capable of decoding and outputting the new hi-rez audio formats ,though that is starting to change.