have driven both, I'd take 997s over the Vantages. it's just a better all around car for everyday use and tracking. sure Aston is prettier, more luxury, and more rare but Porsches are more durable and reliable and more user friendly.
one thing that always got me driving manual Vantages are hill starts, can't use the damn e brake when launching and I hated to give it too much gas afraid to burn the clutch.