At Vairano, it was easily beaten by the 997 GT2 (they have been compared previously; but I'm positive you know this), and just milliseconds off a F430. A similar outcome was shown at Bedford Autodrome's West Circuit where the 997 GT2 beat it by .10. Noteworthy, it was also beaten by the LP560-4. Autoclub Speedway showed the same results, though the LP was slower by .01. Silverstone was the same.
At Laguna, even though it beat them, the GT-R was only able to outrun the Z06 & Turbo by under or just at a second. The 997 GT3, though, did manage to stay ahead of the GT-R. A little trivia for this course btw, shows the Turbo was faster than a previous GT-R time at one point.
At El Toro, it was beaten by the LP & GT2 again, but this time, it did not quickly dispatch the Z06 & R8.
And at Anglesey national, while not a victory, the GT2 & a GT3 RS just got beat by a second.
Some of these are obviously not wins, but I wouldn't go as far to say the GT-R is the best in its class. I'd say, personally, again, it beats out the competition on some tracks, but on others, it either edges out, ties, or gets beat by them.