I have enjoyed my Nissan Sentra LS so much that for the first time in my life I have kept the same car for 11 years. It is fun to drive, comfortable, and has a very small turning radius. The brakes had to be replaced sooner than I anticipated, but overall I had few problems mechanically. The refrigeration and heating systems are still topnotch.
Power windows and door locks including childproof locks on both. Guage positioning. Overall look of the car.
If it hasn't been improved, the body integrity of small items such as rolled door insulating foam strips coming loose. Brakes.