Audi R8 is flashier, more exotic looks. But not really as beautiful as the Vantage or Maser GT.
The R8 has the cool factor of having the engine viewable through the glass like a lambo or ferrari. Whoever said the R8 is better than the Gallardo, wtf are you smoking.
The R8 has a great interior though and overall it's a more complete package, especially when you take into consideration, performance, than the Vantage or GT, but the Vantage and GT are classy and timeless in a way I think the R8 can not emulate and will eventually bee seen as obnoxious.
Audi probably gets the nod for reliability and maintenance costs over the aston and maser.
The Maserati Granturismo needs to be acknowledged a bit more for the fact that it seats 4 adults comfortably. Looking as good as it does... that's quite an achievement. Aston tried it and the Rapide is all right but not nearly as well done as the Vantage, which is the level the Maser GT is on.
Aston Vantage has very little room for luggage so the GT wins in this regard as well. So if someone wanted just one car, the Maser takes it.
But at this point you may already have other practical vehicles in which case it's just a matter of personal preference.
Like I said before, there are slight ups and downs of each like reliability, performance, beauty, but not so much difference in each where it overrides personal desire.
If you want more allure with the girls, the R8 might be #1 thanks to Iron Man and it's flashy looks and visible engine supercar characteristics. The Vantage also fares well thanks to James Bond. The Maserati will do good because it's on par with the Vantage for beauty + 2 seats.
Personally the R8 is a bit too flashy for my tastes and I'd have a difficult time choosing between the Aston and the Maserati.
But in response to the OP, Maserati Granturismo S over the Audi R8/V10 with no intention of tracking in mind.