The 881S superseded the 681EEE as the top of the line Stanton cartridge in the late-1970’s. There’s quite a difference, because the 680/681 is a moving iron cartridge, while the 881S is a moving magnet. Stanton used a rare earth metal (samarium cobalt) magnet in the 881S to reduce the size of the magnet, which allowed them to have lower equivalent moving tip mass than the moving iron cartridges. So although the magnets were very expensive due to the rarity of the materials used in them, they had a performance advantage – according to Stanton they were 10 times stronger in magnetism than conventional magnets of a similar size. Because of the super strength magnet, they could use lower inductance coils and still retain a good voltage output.
According to a Pickering/Stanton insider and former AK member, Stanton employees were initially rather annoyed that their Pickering counterparts had released the XSV-3000 first (around 1976). However, they managed to improve that basic design slightly, so that the 881S initially had a flatter frequency response than the XSV-3000 when it was released.
The 881S frequency response in one review was the flattest I’ve ever seen from a MM cartridge, so it was very good, rivalling some of the best MC cartridges. In fact, it was flatter even than the Shure V15 Type IV, which was the model Shure released as an answer to the 881S, although the 881S was slightly more expensive here in Australia. Julian Hirsh, the godfather of hi-fi reviewing, also showed the response was very flat – in his review in Popular Electronics he rated it at 40Hz – 20kHz ±1dB, using a different test record.
That former Pickering/Stanton manager said that apparently although the information was never released to the public, Pickering later upgraded the XSV-3000 to 881S-level, so the XSV-3000 and 881S were then very similar in performance.
Yes, it's a good match.
It's better, as it was a newer design, and had a flatter frequency response, and lower equivalent tip mass. It was also rather more expensive! The 881S had an equivalent tip mass of just 0.2milligrams, while that of the Shure V15/III was 0.33mg, so the Stanton should track better.
The 881S also initially had a better extended line contact (Stereohedron) stylus tip shape, which meant lower record and stylus wear, and lower distortion, than the elliptical or conical (V15 III-G) stylus used on the Type III. However, Shure later (post-78) released an equivalent hyperelliptical extended line contact stylus for the V15/III, and later still (mid-80's) an even better microridge stylus for it, although tip mass wasn’t improved (the cantilever stayed the same), so trackability was the same for all three tip shapes.
Reviews of the Shure V15 Type III by engineer Julian Hirsch can be found in Popular Electronics July 1973
http://www.americanradiohistory.com/Archive-Poptronics/70s/1973/Poptronics-1973-07.pdf and the Stanton 881S in December 1977
http://www.americanradiohistory.com/Archive-Poptronics/70s/1977/Poptronics-1977-12.pdf.