After reading this post I went back to my Tapestry SACD rips on my PC to listen again, since I respect so highly the opinions of steelydave. I wanted to see if I was hallucinating or something. So I pulled up "Will You Still Love Me Tomorrow" and pulled it apart, track by track.
I was sure that the lead vocal and all vocals were in all 5 channels. Guess what? I was wrong.
The vocals are nicely distributed around the 5 speakers, and James Taylor is indeed "in the back" in the rear left speaker, as he should be. "Get back there James!"
I must have been thinking of the quad, which is mud. So, having said that, please no one be dissuaded from grabbing this SACD while you still can. It really does sound very nice. There are stacks of 5.1 mixes of discs that are worse. I may go over to the poll thread and vote, or change my vote, once I listen to the rest of the tracks.
I stand corrected, and thanks Dave. Good post.