Most likely it was the best Technics tonearm, it was the most expensive tonearm made by Technics, it seems to have the best materials such as metal pipe alloy of Boron and Titanium, and some of the best features such as the lowest bearing friction, dynamic damping, vta on the fly. The EPA-100Mk2 may have a slightly higher standard of machining than previous versions. The choice of metals and way of making the armtube was an improvement. Technics EPA-100Mk2 was introduced in 1982 with TOTL SP-10Mk3 turntable. Matched with Technics TOTL cartridge EPC-100Mk4. The SP-10Mk2A was brought out in 1983. The EPA-100Mk2 was made at a time when Japanese manufacturers were going all out to extend the reach of what was possible.
Let me add Raul's quotes below, he's one of the owner that i know:
Over the last 30 years I don't know any single tonearm design that could beat " vintage " tonearms designs like Micro Seiki MAX 282, Technics EPA 100MK2, Audiocraft AC3300, Lustre GST 801...
Technics EPA 100 MK2: Its unique variable dynamic damping shows the creativeness on the tonearm design along with an extremly stable 4-point gimbal employing ruby ball bearings with a friction of less than 3mg for movement in any direction and the use a metal pipe alloy of boron and titanium. Extremly hard to beat. -Raul