I've found Potenzas to have a really stiff sidewall. Uncomfortable. And I find they aren't progressive in feel at the limits of traction. They hold and hold. And with no warning, they just lose traction. Been caught out a few times.
That's not to say they don't grip well. They do. But where I can feel some other tires losing traction progressively and know how close I am to the limits, I don't have that same confidence when on Potenzas.
This was on the S03s on my Celica, RE050s on a friend's Evo and the "premium" tires on the R35 GTRs at launch.
I ended up preferring Advan AD07s, A048s and the Dunlop respectively.