Yes, as other reviewers have said elsewhere, you really need a multi-channel setup to get the most from this SACD.
I used to have this album in its DG Originals incarnation (still available of course), and at the time felt the recording rather clattery - to such an extent that it rendered the interpretations a blank in retrospect.
Here I did an experiment - I listened to the famous Polonaise op.44 first in CD stereo, which sounded better than I recall it did on the Originals CD, with more body and little harshness in the upper register. The stereo SACD layer was a little better, but nothing revelatory - but in multi-channel: I can only say 'WOW!', simple as that. The sound opens up dramatically with the hall's ambience (the Musikverein in Vienna) brought into play to wonderful effect. The improvement is pretty staggering - nearly in the same class as Yundi Li's DG Chopin CD, which of course was recorded last year, not in 1975 like Pollini's disc. The use of the rear channels here is very clever - DG's engineers have captured the full acoustic qualities of this great hall extremely well.
Performance-wise these recordings are excellent. I've never been a devout Pollini-phile, although some of his recordings are my favourites for certain works, like Schubert's D959 Sonata and Brahms' 2nd Piano Concerto (the earlier recording made about the same time as this SACD). Here he is in imperious form, before the element of coolness afflicted his playing in the 1980s - although I have a couple of his most recent CDs, e.g. of the Chopin Ballades where hs also plays in a freer and almost fiery style, as here.
Most enjoyable perhaps is his large-scale view of the great Polonaise-Fantaisie which comes over superbly here. I know this work very well, and while Richter's Praga recording is probably my favourite, this is also outstanding.
If you've got a multi-channel setup, do not hesitate - otherwise you can stick with the redbook CD in my view. 4.5/5