I've owned several SACD and universal players, with the current incumbent being Unidisk. I've also found that the quality of redbook CD playback on universal players is subpar. That somewhat dictated my listening habit before, as I mainly collected and listened to SACD as much as I can. I have maybe one hundred SACDs, and used to be 70% SACD vs 30% redbook.
Recently I've played with outboard DAC, and other disk players of more recent design. As you probably know already the digital technology has advanced quite a bit in the last several years. I was surprised to find that the redbook playback on a modern disk player is actually quite good. With my new XA5400ES I hear a lot of detail on redbook CD. I'm going through my old redbook CD collection and finding the amount of detail and ambiance usually associated with SACD that I've never heard on redbook CD before.
I think the SACD has peaked in mid 2000 when the redbook CD playback technology hasn't reached the today's level. Many of the labels have dropped supporting SACD since. Today I still buy SACD whenever I can, if there is no comparable CD release, or it's not much more expensive than CD release. But I no longer purchase SACD exclusively any more. The usage is no longer biased towards SACD. I pop in whatever I want to listen to at the time, whether SACD or redbook.