The biggest advantage, of those later V15 cartridges is their ability to track high modulation on the inside grooves. The classical recordings so often end with a big loud flourish on the inside grooves, where the speed under the stylus is lowest due to the short radius. So that ends up being a cartridge torture test. In my view the shure V 15 xmr series are unparalled in this regard. In addition the bass response is deeper and better defined. The top end is also more extended and open, giving excellent reproduction on the high strings and brass. At least on my speakers the improvement in cartridge design and performance improved significantly over the years. The other issue is the arm. You can not assess cartridge performance without taking into account the arm it is attached to. The SME MK III arms were specifically designed to mate with the those Shure V 15 series cartridges. Decca while Stan Kelley was in charge of that division, made sure that the Decca ffss heads would only fit Decca arms, or the SME series II arms with the special adaptor.
Matching arm and cartridge is a lost art, but it is actually crucial. The sad fact is that cartridges in general sit on arms they are not well matched to. Finally the loading capacitance of cartridges is all over the map. Only SME, and especially the Quad 44 preamp, allow for easy optimization of the loading capacitance.
The end result is that the performance most vinyl enthusiasts get from their turntables is way short of the achievable. The vinyl LP is actually capable of outstanding reproduction.
Having said all that, if you think loading a CD into pretty much any deck, or streaming a lossless feed, is a lot easier, you would be correct. For the mass of listeners it gives much more consistent results. To get really high quality from vinyl discs, you actually do have to go to a lot of trouble and understand what you are going. This is not audiophilia and in no way comparable to "funny wire". It is founded on sound electro/mechanical principles and foundation.
