My own preferences are probably different from yours. I care mainly about sound quality. I do not care about 4K. I do not care about Dolby Atmos / DTS:X. I do not care about room correction (I did not like Dirac room correction when I tested it). After testing several HT Processors, I went with a Krell S1200U 3D, which was the best quality sound for my tastes. As I said, the power supply is somewhat undersized at 13,200uf for the analog section (4 x 3300uf). I soldered in another 2 x 15,000uf to these sections. This gave me much more fully and powerful bass, fuller midrange and less brightness/leanness. The Krell Foundation may not have this problem because it only uses op amps. The discrete Class A analog circuits of the S1200 are very demanding on the power supply current.
The Krell Foundation would be missing these features compared to the Marantz 8802a. They are what I call "bells and whistles" features:
- 11.1 channels output (Krell only has 7.1 channels)
- Dolby Atmos surround decoding (not required for 5.1 channels)
- DTS:X surround decoding (not required for 5.1 channels)
- Auro-3D decoding upgrade
- Bluetooth and wireless networking, for DLNA and streaming audio, including Apple Airplay, internet radio, Spotify, Pandora, SiriusXM.
- 4K video processing and upscaling (Krell just passes through video)
For my own personal preferences, I like the high resolution, high detailed, high impact sound for both music and home theater, so I would be choosing the Krell Foundation for myself if I was in your shoes. I think that MC303 is an awesome choice for your future and I think it would match well with the Krell Foundation. For the surround channels, it looks like there is a McIntosh MC152 on audiogon for $3k. I understand if you didn't want to spend this much right now for surround amp. You don't have to. For example, you could throw in something like a low cost Parasound A23 for around $650 for now.
There are other people who like a very laid back warm sound (they don't like the "in your face" detail and impact of the Krell sound). In these situations, the Marantz 8802a would be a better choice for them. It's all about personal preference.
On the AV Receive discussion. You could go ahead and get a Marantz SR7012 AV receiver for about $2k or an Anthem MRX 720 for $2500. This would save you money in the end because you would only need to get an external 2-channel preamp+amplifier or integrated amplifier for your music. The 40% of your home theater listening would not be as good. It depends on how much you really want to invest.
