Technically speaking both SACD and DVD-A formats are superior to any redbook CD.
BUT....
Home playback is so much a slave to how good the recorded information was made. It all boils down to how good the recording engineer did his job at capturing the performance then optimizing it for his medium of choice. Regardless of the media - whether LP, CD, SACD or DVD-A.
At about the time CD made its debut, LP recordings had reached its summit in terms of maximizing the potential of the medium, however flawed and susceptible to all the vagaries of analog encryption. Recording eingeers have long mastered the analog process for decades so that audiophile LP pressings made excellent sonic playback, with some still having no equal up to now. Some of the best analog recordings at the time were rarely duplicated in digital format.
It took another 5 years for recording engineers to maximize the potential of redbook CD. Many of the earlest CDs sounded aweful because their remastering engineers didn't know any better than to literally transcribe 70 microsecond equalized LP masters directly into CD. The result was shrill and bass-anemic CD titles - precisely how the LP sounded without the de-equalization done by phono preamps. Over-eager with the clinical cleanliness of the CD sound, engineers tried unsuccessfully to remaster old recordings with tape hiss by filtering out the hiss, in the process taking out the high frequency harmonics that made LP records more airy precisely because of these. The result - clean recordings without much realism or life. But they learned that the potential of the CD lies not in transcrbing old masters that already sounded excellent in LPs(though the later efforts proved quite successful especially in the new 24 bit remastering), but in capturing the performance digitally to begin with. These days, some of the finest recordings are there on CDs because the reoording engineers have learned over the years how to optimize the CD master.
And at about the same time the CD is reaching its maturity, we now get a new format called DVD-A and SACD which are technically superior in terms of resolving power. But there are titles that are no better than their CD titles. That's because transcribing a 16-bit 44.1khz digital master (often on tape) into 24-bit 192khz DVD-A will really not improve the sonics by any mathematical stretch. For the new format to achieve its potential, you have to start with capturing the performance at 24/192. Not just transcribing previous masters into higher resolution. Same with SACD. There is no way a 16-bit master remastered into SACD or DVD-A can sound superior. (however, remastering from 2-channel to 5.1 channel is another thing. Done correctly, it may not sound better, but more engaging and more detailed.)
There's another caveat here. No matter how powerful the resolving power of the recording, if the recording engineer is a nitwit, you still end up with a lousy recording. In whatever format.
So personally, if you come across a truly excellent recording. Get it. If it's on LP. then get the finest turntable you can get. IF its a CD, then get the best CD player you can get. If it's a DVD-A or SACD, then get the best universal player or separate you can get. Lemons exist in all formats. As well as real gems. It would be a shame if you missed a great recording on one format because you prefer one over another. Having said that, I myself have cast my lots on digital. I have had 5 years of LP prior to my switch to digital. That's enough. There are so many titles on CDs that sound great by any standard. OTH, there are so few titles on DVD-A and SACD that my plans for a really great universal player can wait. I will certainly miss some of the great recordings on LP. But that's more a decision based on convenience. And in the hope that there will be new artists who will record those great classical performances in LP with better digital sonics in the future done by golden eared recording enigneers.
With all the titles in CD, you can never go wrong with a great dedicated CD player. But with the advances and refinements in DVD home playback systems that get in every year, the finest universal players for DVD-A and SACD can also sound great playing CDs. Online reviews talk about some Denon or Yamaha flagship universals that can shame some of the most expensive CD players like the Theta brand(which is said to be just a Pioneer Cd player rebadged and re-housed actually). Thanks to technology (and your wallet), you sometimes don't have to choose as you can have the best of all worlds in one neat package.