Comparison of sonic qualities of some tonearms

@mijostyn You state that between tonearms “The difference in sound quality is so slight as to be made meaningless and subject to psychological overlay.”  
If that were the case, then why would there be so many different types, manufacturers, and grades of tonearms?  It is possible that many listeners are of the same opinion as you, namely that a tonearm makes little difference in sound quality, because very few even discuss tonearms in these threads.  However, in my very limited experience, I would say that a tonearm is capable of making as significant a difference as a pre-amplifier, or phono stage can make.

@lewm The 80's was a time when the MC was beginning to Supersede the MM Cartridge.

MC's are best served with a medium mass arm, well that is what Rega believed and got to work on their designs.

SME were quite focused as a Company of the lightweight arms most suitable to MM's.

The second thing that happened was that Cast Arm Tubes incorporating the form of the Headshell were discovered to be very very attractive by the Press and numerous others, hence Rega's affordable arms were not, according to the mainstream media, just merely a Giant Killer, they singularly decimated legions of Ork's.

Shortly after this nearly all very well established Companies started to make it known about their Cast Arm Tube Designs with formed Headshell and some even had their first MC Cart's produced in conjunction with the debut of the TA.

If Rega had been more protective, the plagiarism would have been a lot less at thei era in time.

Without the Rega on the Market stealing multiple sales from the Big Names, there will not be a SME V and IV chasing its market share.

Anybody who is suggesting a V or IV will trounce a well honed design for a Rega TA is giving very misleading information, the materials used on either might be the only real detectable difference to the produced sonic, the extraction from the Groove are way too similar as a result of the designs for each and how the design allows for the interface with the Cart' set in the Groove.    

The first MC cartridge to make a sizable dent in the US market was the Supex, in 1973-ish. Perhaps your living in the UK gives you a different perspective on Rega and SME, but Rega were a nonentity in the US market until the 80s, and there was no general consensus on materials to be used to build a tonearm back then, just as there is no consensus now.

and then some tonearms are more equal than others :)