Compare the Mercedes GT AMG Roadster - [2017] vs Bentley Continental GT 6.0 W12 Turbo - [2017]. Find out which car is the fastest, most powerful, lightest or has the biggest engine in our top trumps style comparison page. Find out which car has the highest top speed or is the fastest accelerating, is it the Mercedes GT AMG Roadster or the Bentley Continental GT 6.0 W12 Turbo. We'll leave it up to you to decide which is your favourite.