Had a quick look at this over at my mates today, very very good looking game, GT5 is going to have to work hard to improve on this - by the time it arrives it probably will look better but right now this is the best looking racer out there.
I've not encountered any frame hits yet, although I've not played it much either. But graphically PGR4 is a mile superior to (the still gorgeous) PGR3.
I've had ONE framerate issue, but only minor.
Was on one of the New York tracks, about 4 or 5 racers (me and 4 AI) turning a corner, in the rain, and just as you sped up it juddered a little. Can't emphasise how small it was, but was noticable.
Other than that, flawless.
I only had one area for framerate issues in PGR3, that was also New York when hammering it over the Brooklyn bridge, does it not stutter there anymore?
It does for me, but only during replays from a zoomed-out view. Most of the time the game runs flawlessly, but I seem to take performance hits on certain tracks when I'm in a very fast car and theres heavy rain.