The Mercedes-Benz GLS attempts to emulate the panache and presence of the S-Class in an SUV package catering to the needs of large families. Its highly capable powertrains all feature mild hybrid technology, with output ranging from 375 hp to 603 hp. That top rating is achieved with the AMG 63 4MATIC+ model. The GLS also offers an ultra-opulent and exclusive model wearing the prestigious Maybach badge. Chief among this full-size SUV’s drawbacks are high prices and reliability issues.