2003 Impalla purchased in July 03, now has 65,000 miles, 25-28 mpg city, 30- 34 interstate highway mpg, just amazing for a car this size. Very reliable, no problems since purchase, by far best car I have ever owned in my life, and I am 55. Compared to previous Chevrolets I owned from the 70's, 80's and 90's, they have done some darn good engineering.
Gas mileage, ride comfort.
Location of the oil filter on 3.4 liter engine. Very difficult to get to and change.