I tried the R 888 for one day. I didn't heat cycle them as it was a last minute purchase. The fist session they had far less grip than the PSS. By the third session they had more. I hated the tread noise and movement......I could feel the tread moving the car side to side. I used the recommended tire pressures but don't think they liked the heavy car.......and I didn't like them switching to another option the next day.
It will be interesting to hear others opinions after experiencing the R888.