not sure about the newer ones, but in general i think they are pretty fucking awesome performance wise, obviously other cars in the same price range will beat them in all out performance, a gt3/gt2, like any ferrari, etc.. is obviously going to be better in outright performance. but for the 99.9% of your driving, even if your a hardcore enthusiast, an aston will perform better. how often would you go cruise mountain roads in a ferrari entering a turn at 120 carrying a slide from entry to exit? not that often im guessing.
cars like astons and amg's are awesome for when your driving the car at 95%. and when you take it to its limit, its still good, but thats where it looses to other cars.
i got to drive a 2001 (i think?) vanquish, i know this guy who owns a dealer that sells high end cars, i took it on some mountainish roads, highway, normal streets etc.. for an hour, and it was amazing, power at absolutely any rpm, perfectly balanced, you could get a little rotation on entry and use the throttle to balance it and pick up a slight push at exit, just super good for driving anything super fast, just not retardedly fast for public roads. and ive driven many cars that technically perform "better" but not many cars do as well for the kind of driving you do on public roads.
sorry, just had to defend my love for fast as shit luxury cars.