Tuff questions, similar cars yet different cars too. The Vanquish is going to fell a bit more sporty. The Continental GT is going to pull without a problem but will ride a bit softer. I have driven both and would pick the Aston Martin based on its design, and the exhaust note isn't as tame.
Both are great cars. Drive them and then decide which is right for you.
Both are great cars. Drive them and then decide which is right for you.