The new third generation of the Mercedes-Benz GLS is here. The car that in many ways can be credited with the segment's global popularity, the GLS has for long been the luxury SUV benchmark. The new model brings improved performance, massive leaps on technology and more credible off-road cred. We test the variants that will come to India in 2020, where it will need to compete with everything from the Range Rover to the brand new first-ever BMW X7.