There is no best or perfect unipivot, or even tonearm. The performance of any tonearm has to be viewed in the context of the rest of the playback system - the cartridge and the turntable. How has the cartridge designer dealt with unwanted energy - have they dumped it into the arm, have they designed the cartridge body to dissipate it ? What about the turntable tonearm interface, metal, polymer, composite, wooden materials used ? All these choices will impact the performance of the tonearm.
From the Durand site -
"When a musician goes to a luthier or an instrument maker to buy an instrument he/she doesnt spend too much time on the issues of engineering--although the materials and techniques used in the construction can be of the highest interest; the musician plays the instrument, and listens. He wants to know if the instrument can do what he wants it to do, if it produces the sound he wants to hear
Choosing a tonearm involves the same process."
The Durand is a tone control - no problems, if it produces the sound you like then thats fine.
My current unipivot tonearm of choice - Naim Aro, used with Koetsu & Dynavector Nova 13D Ebony. Does not work with MM's or Ikeda Kiwame also owned.
Would like to try - Graham Phantom Supreme, Spiral Groove Centroid and Telos.
Any of these should be pretty good assuming they match the cartridges chosen. What my experience was as a dealer was that any differences in these arms could be easily lost or reversed through sub optimal set up.
What I do like about unipivots is their degree of freedom to the sound, the ease of presentation, but they will not always be the best choice as alluded to above.