The Vanquish is a very beautiful car no arguement about that, but if you want reliability and good looks, go with a Ford Mustang.
I've had cars that have had 1000 miles a year put on them tops... if that. Plenty of time to have issues corrected. So you drive something else. But the 1000 annual miles are a blast and you have a piece of art in your garage even if not driven. Some people do not get that aspect of ownership however. Like my spouse!
Rule number one. Never buy a brand new car, especially an expensive one. Instead, buy it 2-3 years later on the used car market. That way, depreciation will have taken an almighty chunk out of the purchase price. I'd expect at least a considerable number of niggles and faults to have been sorted through recalls, etc and if you're lucky, you'll still have a decent bit of warranty left.
Better still, with reference to Aston Martin's in particular, why not just get a much older, classic 1970s or 1980s one? It will probably have been restored by now, or at least cosseted all its life, which reduces the chances of anything major going wrong, it won't depreciate like any modern one, it'll be much cheaper to buy in the first place, and if the stars are aligned right... it might even increase in value during your ownership. Fair to say it's a potential investment opportunity.
... and (in my humble, subjective opinion), those classic Aston's look far classier than anything that's been produced after Ford's ownership of the company.
Spend half and buy a new Corvette supercharged. Over 600 hp, extremely reliable drive train, and goes 0-60 under 4 seconds and 200mph. Many buy 2 or 3. Take the other 100 grand and take it on a long cross country vacation. And then drive it to work when you return. I pretty much do Mobil 1 changes and tires. That's it.
You have a point when it comes to performance/value for money, but it's not really a fair comment to make, since the Corvette is aimed at a completely different type of buyer to the Aston Martin.
Go with the 2014 Corvette waiting list. Restyled, European inspired interior. Why spend more time in the shop than on the road? Some I know have 3 late model ones in their garage. Coupe and Convertibles. Just a suggestion. Take the dollars out of the equation and buy a supercar.