edited the OP post to include:
After their release the reviews are starting to roll out. Road and Track had one of the first reviews:
Road & Track PS4S Test
TLDR;
"All of this was summed up to me on the autocross course where the PS4S were able to produce the strongest data—but what really set the PS4S apart for me was its ability to remain consistent and produce more grip and more roll resistance as the pressures and temperatures built up. Admittedly, I was ragging the tires past their limits, but what else would you expect?"