I'll toss in what I know. In comparison between the 105 and 205 series, the 205 series loses the following items:
- 205 will not support streaming services (Netflix, VUDU, Picassa, CinemaNow, Film Fresh, Youtube, Pandora, Rhapsode). They are getting out of the streaming business, so the 205 will not stream directly from these services by itself. If you do have another device to stream (such as Roku, Amazon Fire TV, laptop, etc.), you can stream the content and send it to the 205 using HDMI, coax digital, toslink (and possibly USB input).
-205 does not include DARBEE processing. Darbee is an image enhancement DSP process. If you play hi-def 1080p mostly, it may make a very tiny improvement in video quality. Darbee will excel in improvement image quality of low-resolution 480i DVD type sources.
-205 has a power supply about 2/3rd the size of 105. I suspect the power supply was reduced in size because the digital board no longer needed the DSP required for Darbee and streaming services.
Now the "positives" for the 205
- Supports 4K video (if you need it).
- Appears to have an improvement in analog audio quality due to the newer Sabre DACs used and they design/layout of the analog boards.
I'm sure others will chime in with their observations. In the end, I think it depends if you feel you need 4K and the improved audio quality, and are fine with losing those couple features.