Blu-spec CD is not a new audio format says Sony, it's just CD made to sound much better

HDCD required a player with the necessary decoding capability, and as these discs don't, I can't see the connection you're trying to make.

SACD has failed because the average punter wasn't prepared to fork out more money for little or no perceived improvement in quality, much the same as Blu-Ray will not succeed DVD. That at least, together with no guarantee of better quality control over the mastering process.

This is about Sony trying to make better sounding CDs and that is to be applauded. Very well mastered CDs on good equipment do sound superb and if the quality of the mastering is improved then this has to be a good thing. It's also quite clever, because collectors will be tempted to buy a title they already own if they're likely to get a better recording.

Whether it's CD, Blu Ray or Gamma Ray, the quality of the mastering is by far the biggest variable when it comes to all round sound quality, especially with older material,much of which has previously been rushed out just to cash in on an album's popularity. The best (well, worst actually) example of this I have in my collection is Lamb Lies Down on Broadway by Genesis. The LP was a classic example of a great pressing in my view and popular with audiophiles at the time, but the CD has so much background noise and compression it is unbearable and literally unlistenable on decent gear.

As Sony probably has control of the world's largest single catalogue of recorded music, any attempt by them to raise the standard is good news as far as I'm concerned :)

I have been a Recording and Broadcast technical Engineer since the 1980s. I was instrumental in the introduction of Digital Recording systems into the UK Recording Industry, and was a CD mastering engineer for several years.
This is pure marketing hype!
OK so Sony can now make better Glass Masters, which will probably make the glass master last longer & produce less manufacturing failures.
But it will make no difference to the sound as heard by the punter, no matter how good their equipment is.
A CD has 16 bits, and samples at 44.1khz, thus giving a theoretical dynamic range of 96dB & 0-20kHz frequency range.
Servo jitter is caused by keeping the laser following the pits as the disk spins, its not the sharpness of the edge that casues most of this jitter, but the eccentricity of the spiral of pits, the blue laser will not improve this. If the player's electronics is designed properly all jitter, and any errors in disk reproduction will be corrected, note error correction is mathematically 100% accurate, digital data has only 2 values 1 & 0, if the laser reads a 0 & the correction system knows its the wrong value, then it changes it to a 1, i.e. the original value! It is not possible to hear error correction, because correction results in the original data. Its only when the data loss is so bad that error correction cannot cope, and concealment is used, that it becomes audible.
As to jitter, all digital systems have jitter, its intrinsic in how the electronics works, jitter is only a problem when the data is converted from one form to another, i.e. when the microphone signal is digitised, or when the CD signal is converted into analogue so it can be heard. Any jitter in the signal being read from the CD is removed by reading the data into a buffer (memory) at the jittering rate, then reading it out again under the control of a very low jitter master clock.
What makes a difference to the sound of a CD player, is not the transport & disk laser system, but the accuracy of the Digital to Analogue conversion, the 'quality' of the low pass filtering (to remove all audio above 20kHz), and the prevention of cross-talk from the digital electronics getting into the analogue electronic circuits (noise induced on the power supplies, radiation etc).
As John Watkinson commented when referring to digital interconnect leads, if the sound is changed by the replacing of a cable, its because the equipment has not been designed properly, not the quality of the cable. The same goes for these Blu-Spec CDs, if they sound better than ordinary CDs on your CD player, then the CD player was not very well designed. Or perhaps more care was taken at the mastering stage that produced the digital master tape used to make the CD Glass master, but that would make an ordinary CD sound just as good.
Anyone who pays out hard earned cash for a Blu-spec CD wants their head seeing to.
As to SACD, this is a vastly superior delivery format, and despite what was stated above, it is very clearly audible, even to un-trained ears, providing the material justifies it, much modern ‘pop’ music has its dynamic range squashed to death, so that it sounds loud on the radio, and the production standards are often very low. Whereas some artists have made use of the wide frequency response and large dynamic range SACD offers resulting in stunning recordings. The old adage GIGO springs to mind, ‘Garbage In Garbage Out'.
Hybrid SACDs will play on any normal CD player, and it is possible to have a stereo CD mix, a stereo SACD mix and an SACD surround mix, all on the one disk. Thus providing a single inventory, one disk that plays on all players. Sony should put their efforts in promoting SACD not this Blu-Spec CD rubbish.
And don’t get me started on MP3 and other data compressed formats.