Cadillac STS vs Infiniti G35?

i am interested in buying a new car but i cant decide between the Cadillac STS and Infiniti G35(coupe). I like that the cadillac has 5 seats compared to the infiniti which only has 4 seats. The deciding factors are which one looks better and which car is more reliable (performance). Ive always liked sports cars and the infiniti is a sports car but ive wanted a cadillac my whole life unfortunately they dont make cadillac sports cars which more than 2 seats and i need a car with at least 4 seats but i prefer 5. I think they take up the same amount of gas but if one takes up less than the other than thats also a deciding factor. so which car is better the cadillac or the infiniti?? i already own a sports car (toyota celica) so maybe some people would want only one sports car and one luxury or maybe two sports car i want your opinion. also which would give me a better reputation for having a good car? i love the woodgrain on the STS but i hear the inifinitis are good all around? opinions?