I'd actually like to see the every day person take both the Vette and Cayman around a track and compare their times.
Not long ago, I think that despite the power shortage, the edge might have gone to the Porsche in that test. Today, with the significant improvements to the Corvette chassis and it's superb electronics, I'm not so sure.
If it were my own hard-earned money, yeah, the Corvette is a winner thanks to the super-aggressive pricing. And when the money gets to the $100K mark (which can happen even with a Cayman...) then suddenly the 620hp Z-06 comes on the radar.
But, yes, the Cayman GTS and the R (especially the R!) are DED SEXY.