Standard Mercedes warranty is 4 years 50k miles. You can buy the extended 7/70-100k warranty before the 4 years is up. There's a bunch of dealers mentioned in the one of the Mercedes subforums on mbworld.org that will discount the extended warranty.Warranty for this car is 40k mileage (bumper to bumper i belive.)
This is the worse model i own. Better to buy GLE350
rattle noise inside the car
air not cooling enough
Typically on Mercedes, it's the lower priced models which get the most complaints as MB cuts corners to meet the lower price point. Also I always felt their motto, the best or nothing basically referred to their options and engineering, not to their reliability. Certain things are definitely worse on a Mercedes than other cars. I like them for all the options they have and some prefer them for their safety features which you still won't find on other brands.