Rrog: I and others care about an optimized set up. It's that simple. Lots of other people want to play with cables and tweak the sound to their liking and/or add or subtract "things" to the sound for better match in their systems - that's a valid approach AS WELL (but not necessarily optimal). They may even get "better" results. None of this implies that what Spectral is doing is wrong or not based on solid engineering principles - it's just not to some people's tastes and goals. I personally have no qualms about the performance of the top MIT/Spectral cables, and am glad I don't have to overspend on cables. In fact, I have compared them to higher-priced MIT cables and still find them superior (that could also mean that MIT is generally producing colored cables, and I am a strong believer of that).
Advantages over other amplifiers? I haven't analyzed other amplifier designs, other than to observe that other edge of the art SS gear, like the Soulution, are also wide bandwidth designs - wide bandwidth achieves (or aims to achieve) extremely fast circuits, which theoretically follow the signal more closely - the sound Spectrals and Soulution achieve is probably testament to that. I don't know if these other amplifiers filter the output inside the amplifier or not (and an output coil is very easy to spot but I have not seen close-up pictures of the units), but I have also observed they include ventilation fans, so there is a possibility they don't filter but achieve optimal thermal operation by blowing air in and out of the unit, which would let one play with cables - that's fine too.
Another edge of the art vendor, FM Acoustics, also believes in fine-tuned amplifier/speaker interfaces. You should read http://www.fmacoustics.com/pdf/audiophilpoweramp.pdf and take notice of a couple of claims:
1) "One of the most important characteristics that determines the quality of the entire system is the interface between amplifier and speaker."
2) "In amplifier-speaker interfacing a variety of criteria have to be observed, and the ideal cable has an optimal mix of these criteria."
3) "The criteria that has the most significant influence on the transmission quality of cable - the transfer characteristics - is often neglected for some other - often visual - aspect."
4) "As no wide-band width cable of this calibre is available as standard, engineers at FM ACOUSTICS in co-operation with the world's leading experts on cable technology have designed a unique cable that features a variety of proprietary characteristics. FOORCELINES guarantee optimal signal transfer, truly highest damping
and perfect control of the speakers."
So there you have it - another manufacturer that uses specific, optimized cables for their needs.
The bottom line is that what Spectral, FMA and others are doing is nothing but *optimal implementation of transmission line theory*. To everyone else, it's just a cable that can act as a tweak. Personally, I have been sold on wide bandwidth designs and transmission line theory decades ago.
You may still think Spectrals are not worth the trouble - and that's fine with everyone. I am surprised, though, that you brought up the cables as being the limiting factor and not the requirement for their preamps (and a lot of that has to do with stability into the MHz, proper output impedance and ample amperage to drive the amps), except for the inferior "S" versions of the amps...