Well, the SCD-1 and SCD XA777ES leave me cold when they are used as CD players, with the redbook going through the Sony DAC. However, when one hooks them up to an external DAC, such as a Zanden Model 5000 DAC, all is forgiven, and they take on the warmth, smoothness, and musicality of the best CD players around. Needless to say, they make great CD transports. Their former "deadness" and dry sound is easily rectified, albeit with considerable stress on one's wallet.
Really, I think it is more of an issue with the DAC than anything else. They make great transports, and the SACD playback is incomparable, far in excess of what the best Redbook can offer. The details are all sharper, and the soundstage is widened to quite a large extent under SACD playback. That said, the Marantz CD-7 offers most of that performance for very much less.
My guess is that the SCD-XA 777ES makes a good audiophile transport, and a decent player. But as an audiophile player it is bettered by the Marantz CD-7, which has most unfortunately, been out of production for quite a long time now.