2017 Bentley Continental GT V8 S Convertible vs. 2017 Mercedes-AMG S63 Cabriolet

Dad bought a new Cadillac Eldorado convertible in 1976. GM touted it as the last of the big droptops, a majestic parting shot seemingly designed to transport prom queens, grand marshals, and Boss Hogg types into an increasingly ­dystopian, gas-rationed future. Dressed in triple red with every option, including fuel injection, automatic high-beams, power everything, and a hard tonneau “parade boot,” that 18.7-foot luxo-barge weighed 5231 pounds and was motivated via an 8.2-liter V-8 under a hood so long you could land an Airbus A380 on it. No one can say that Cadillac let the convertible go g­ently into that good night. What no one could have imagined back in 1976 was that big ­convertibles would exist at all 40 years later, much less as 500-plus-hp chariots for the same well-to-do neighborhoods that Cadillac once owned. In a world of $2.50 gas and ever-growing stock portfolios, the parade car has returned. Using a big, thirsty, open-air sled to declare “I’m rich and deserve this” is again possible without having to resort to the classic-car market.

After a four-decade hiatus, Mercedes is back to building full-size convertibles. Save your letters; we’re not counting the E-class–based 1993–95 cabriolet because it did not achieve true pulchritude. In no dimension, except maybe build quality, does it measure up to this S-class–derived four-seater. Available in three flavors, Merc’s convertible is a leather-packed bullet aimed squarely at the Bentley Continental GT convertible. Constant updates have kept the now 12-year-old Continental as relevant as any car costing more than $200 large can credibly be. Admittedly, when conducting a comparison of cars this ludicrously expensive, logic is trumped by baser stuff. Cadillac certainly wasn’t thinking logically when it built its 8.2-liter V-8. Just as with old stars that grow so large they collapse upon themselves, Cadillac’s 500-cubic-inch supergiant, in its final year, made just 190 horsepower (215 with fuel injection) and 360 pound-feet of torque, numbers that Mercedes can now match with a 2.1-liter turbo-­diesel. But with two turbochargers and more than 500 horsepower each, these modern V-8s certainly recall that Cadillac’s excess.
Bentley and Mercedes do offer larger 12-cylinder engines, but we chose the V-8 versions because upping the cylinder count adds weight, complexity, and cost without, in our opinion, improving the driving experience. Okay, so sometimes logic does trump ­emotion, even in the illogical world of the big convertible.

On the Mercedes side, we selected the 577-hp AMG S63 that starts at $178,325, here to do battle with the 520-hp Continental GT V-8 S convertible that opens at $234,525. AMG’s 5.5-liter blown V-8 is the perfect foil to Bentley’s 4.0-liter blown V-8. Because it’s not exactly Bentley’s engine—it’s the same unit found in a number of Audis—this is sort of a proxy war between two German rivals.

Cloth-top, two-door personal luxury machines might perplex those of us without vacation homes and yachts, but as with the Eldorado of the ’70s, there’s a seductive magic to a comfortable, tech-filled premium convertible with a V-8 heart.