I have owned my Infiniti G35 6mt coupe for almost 2 years now. I have app 22,000 miles on it and I can say I am ready to get rid of the car, the issues I have are the expensive oil changes and maintenance costs for example the tires. The ride quality is rough and after 15k the rattles start to be heard due to the poor construction of the cabin. The driver's seat position is very tight leather wears quickly. The non Bose audio system I have is absolutely horrible. The speakers and dash appointment look like they are straight out of an Altima for years ago. The car is also the worst car I have ever owned in the snow despite 4 snow tires. The shifting linkage is not crisp.
Color, experior styling, dealer service for all of the times you will need to bring it in for warranty service due to poor build quality.
More refined interior, better audio options, ride quality improvement by actually tuning the suspension. Steering feedback is muted and turning radius is awful. Backup lights and blind spots leave a lot to be desired. Shifting is choppy and lacks crisp feel of other similarly priced sports coupes.