I've had my 2009 Aveo for one week and so far so good. I'm impressed with how quiet and smooth the engine is. I've had many GM 4 cylinders since 1977 when I bought a Pontiac with the Iron Duke. Currently I also have a 2007 Vibe and the Aveo engine beats it hands down when it comes to noise and vibration. I got 36+ MPG on the first tank. I'm surprised how much I like driving it.