What @myjostyn is referring to is the inability to repeatability, reposition the arm after cart changes and the like in the exact same spot where the pivot point aligns exactly in the receiving cup as before. Also if one doesn't very carefully/slowly handle the arm when changing records, this alignment can get off slightly.
If owners of the 3D uni haven't noticed this, they must be perfect or not paying attention.
I use the dual pivot with my PEEK film upgrade to great effect.
