[Dilettante]

Bill,

As far as sound quality the 105/205 would be much superior to the 103/203 when using the analog audio outs. The 105/205 were designed and built differently than the 103/203. The 105/205 have separate and better power supplies, a dedicated stereo analog audio output stage, better DAC implementation & configurations, better power supply regulations and implementation, etc.

But if you want to connect everything via HDMI out of the Oppo player to your AV pre pro the 203/103 will be better choice since you are only using the Oppo as digital disc transport if you connect via HDMI out or coax digital out or optical digital out of the Oppo player and can save some money.

Since you already have the 203 for watching movies and you stated that the 105D is en route, well......you can use the 105 for CD, SACD & DVD-Audio playbacks and run the analog audio outs of the 105. You can also use the 105 as a standalone DAC since it has various digital audio inputs on the back as well as USB DAC. And use your existing 203 for 4K UHD & bluray movies via HDMI out. The 203 has no streaming features whereas the 105 does. With the 105 you can stream Netflix, Vudu HD movies, Tidal & Pandora music streamings. The 203 has no streaming platforms at all. You can also connect the 105D via HDMI out to your AV pre pro for Netflix & Vudu HD movie streamings if you are into streaming movies. If not, just run the XLR analog audio out of the 105 to your preamp or stereo integrated amp or pre pro.

The 105/205 or the Oppo in general are jack of all trades or like a Swiss Army knife and does everything well. But if your main focus on 2ch audio music playbacks there are dedicated 2ch audio only machines out there that will sound better than the 105/205 but they usually cost lot more than the Oppos. All Oppo players are true bargain and very reliable and have top notch video qualities (picture qualities) when playing movies. When used as a video player / transport using HDMI out, the Oppo will be your best bet. The Oppos will play 4K, bluray & DVD movies flawlessly and video qualities and upscalers are top notch. Plus all Oppo players are very reliable and durable and will play any media discs reliably.