2 channel SACD vs Multichannel SACD players...

Without going into the science, I will just say that I have owned two multi-channel SACD players, but have used them both exclusively for two channel listening and they have both sounded great in two channel.
When it is said that a SACD player is multi-channel, it means it means it
can play in both two-channel AND Multi-channel. When it is said that a
SACD player is Two-Channel, it means it doesn't have multi-channel
capability. Personally, I think some multi-channel SACD players sound
better in Stereo than in multi-channel, but since I have a strong preference for two-channels when it comes to music -- I am probably
too biased in that regard to render an objective opinion.

Rsbeck, I am a two channel person myself. Have you had the opportunity to listen to 2 channel SACD from a dedicated 2 channel player? If so, how did it compare to 2 channel reproduction from a multi-channel system?

There is absolutely no technical reason why playback of the SACD 2 channel program should be better or worse than the 5 channel one. Of course the 2 channel mix might be more to your liking than the multichannel mix, but that is a function of the disc, not the player.

Some confusion may result from the DVD-A 2-channel capability, where the stereo mixdown is done by the player using information provided on the disc by the recording engineer.

Well here I go again, "....DVD-A 2-channel capability, where the stereo mixdown is done by the player using information provided on the disc by the recording engineer."

There is proprietary two channel information on a DVD-A disc?

I know there is always proprietary 2 channel info on SACD. I might add that, in a 2 channel only SACD player, it stands to reason you could get higher quality construction because of fewer channels. That should be fairly obvious.

Distortion...A two-channel program does not exist on a DVD-A, but instructions to the player regarding how to mix down the multichannel program into stereo are there. The DVD-A approach and the SACD approach accomplish the same thing in different ways. The DVD-A way doesn't use up as much data space on the disc, (for a complete 2-channel program) but requires a mixdown capability in the player.

Hardware for the three extra channels of a multichannel player cost almost nothing.