I absolutley love my Cavalier. I've had it for over 5 years now and I have not had a problem yet. It was previously a rental car before I bought it so I thought it would have major problems. I was completely wong. I replaced my brakes at 53,000 miles. Other than regular maintenance, it hasn't had any problems. I couldn't have asked for a better car. I get about 35 MPG on the freeway and about 30 in the city. I don't know why I get such good gas mieage (I live in Southern California for goodness sakes, I am always in traffic!). I plan on driving it until it will not run anymore because it of the gas mileage.
Mine didn't come with powered windows which kind of stinks. It did come with a keyless remote and alarm, which is nice!
I don't think I would improve anything on it. I have no complaints at all. I feel very blessed for my car not having any problems and getting excellent gas mileage.