This is the best full-size-premium crossover for you if you desire the S-Class of SUVs. Conjuring the performance and prestige of its flagship sedan, that’s whatMercedes-Benz calls this all-new version of its seven-passenger SUV. It’s not all hype; the 2017 GLS-Class is spacious, luxurious, feature-packed, and fast. Indeed, the name itself reflects its station. The German automaker has rebadged its crossovers, beginning each with “GL” and adding a third letter to align it with a passenger-car counterpart. For example, the midsize GLE (formerly the ML) identifies with the E-Class midsize-car line, and the GLS with the full-size S-Class sedan. The original version of this three-row crossover debuted as the GL for model-year 2007. The redesigned third-generation 2017 model is virtually identical in size to its 2013-2016 predecessor.Buy the ’17. It’s all-new, so aside from maybe some new paint colors, expect no noteworthy changes for 2018 – although prices are almost certain to increase. The lineup should reflect the ‘17 roster, as well. There are four models: base GLS350d (d for diesel), the V-6 GLS450, the V-8 GLS550, and the V-8 GLS63 tuned by Mercedes’ AMG performance division. We applaud Mercedes for positioning the GL350d as both the least expensive and most fuel-efficient model, though even it acknowledges most buyers and fans of this luxury model will select one of the gasoline-powered versions.It’s not easy to see the visual updates to the 2017 GLS versus the outgoing GL, but they’re there. Most noticeable are the new grille with its massive Mercedes logo and reshaped headlight housings that curve down and in, for a more sinister look. The tail is recontoured to present a broader, more planted look. Differences between trim levels are minor, running mostly to wheel sizes: 20-inch-diameter on the GLS550 and 21 on the GLS63, versus 19s on the other models. Even the GLS63 is only subtle distinguished visually, mainly by a slightly deeper front fascia and quad instead of dual exhaust tips.For the gas, city/highway/combined ratings are 17/22/19 mpg for the GLS450; 14/18/16 for the 550; and 13/17/14 for the GLS63 AMG. All gasoline models require 91-octane premium-grade fuel.Probably not a whole lot until a midcycle freshening, probably around model-year 2020. Increasingly stringent fuel-economy regulations could mean the demise of the GLS550, if not also the 63, but that’s up in the air at this point.Competition Audi Q7, Cadillac Escalade, BMW X5, Range Rover, Lincoln Navigator, Lexus LX570, Toyota Land Cruiser but Mercedes is a brend that everyone would love to have.