I think the F1AS2 is a lot more suitable to lighter cars for track use or less power/torque maybe when used on track? I say this simply because people with heavier cars, E46 M3, RS4 have chewed through the F1AS2 within a day on track, yet those same people moving to PSS have seen vast improvements, especially on track performance and lifespan.
Its why I'd like the PSS for the M3, so when I am using it on the road, its get superb road ability too, plus the fact they will last 2-3x longer than cups and give near cup dry ability but with far superior road and wet ability.
The 911 has two sets of wheels, I was running the Pirelli Pzero Corsa, which is a semi-slick but with full tread depth for better standing water ability, standard fitment on GT3 and N-Spec, which Porsche recommend for road/wet use over cup tyres. But as soon as temperatures were below 10c and wet I literally had zero confidence on this tyre in the 911. The car was twitchy, skittish and just felt dangerous. Bear in mind these tyres are quite new, only about 1000 miles on them and over 6mm on the rear. I still however decided to change to my nearly worn out PSS on my other wheels, only 2mm on the rear. The dramatic change to the car is simply night and day, it can be just above freezing, wet and yet I can drive with full confidence and at speed on them. In warmer weather on the road the PSS is a match to these tyres, the Corsas are a little better on track and their stiffer sidewalls give them better turn-in which is highlighted more so on track, hence why I got them.
That is why I like the PSS so much, I can beat on them on track and get a lot of track days out of them, I can drive hard on the road for thousands of miles and they work absolutely brilliantly no matter what the weather conditions and also give superb feedback, response and confidence. More importantly they work as good now they are nearly worn out as the day when I got them, I've had so many tyres that at half their life perform nowhere near as good as they did at the start of their life.
I am not knocking the F1AS2 its clearly abundant it is a superb tyre for the road and it specialises in wet conditions. In the recent EVO 2013 test it did very well, but they did rate the Yoko V105 sport better for feedback and lap times both wet and dry I believe if I remember, could be wrong. In the review I posted earlier the PSS was shown as better than the V105 Sport which EVO showed as being better than the F1AS2 if your requirements are more sporty and you do track work. But like Rich says, tyre reviews can only tell you so much, it is factual that different tyres work better on different cars, without a doubt.
It would just be nice to have PSS in more sizes so they were available to more, for me its not such a huge issue any more because next year the cup2 is released in my sizes which incorporates the improvements of the Supersport into the new cup tyre, so longer life and improved wet handling ability, plus even crazier dry ability.