What we have here are two Sedans from Lexus with some differences, such as the model year, horsepower, fuel economy, market segment, and ground shadow size. First of all, the is a newer vehicle by 3 model years. Also, the 2013 IS 350 has bigger and thirstier engine; the 2016 ES 300h gets 18 more mpg. In addition, the ES 300h has a slightly larger body than the IS 350. Among similarities are the body structure, market segment, starting price, height, and maximum occupancy.