Just bought the 2014 Mazda 6 sport last week. It's a great car. It's design and handling really make it stand out among midsize family sedans. It won't win any drag races but it has competitive acceleration for it's class and gets great gas mileage. I am averaging 29mpg with about 50% highway (60-65mph) and 50% city driving. Some things I have noticed: Plenty of backseat space, gigantic trunk, smooth transmission, suspension stiffer than others but results in better handling, road noise is acceptable but not the quietest and the base model radio stinks but that's to be expected (will upgrade soon) I highly recommend. At least test drive it.
Smooth auto transmission, base model uses aluminum rims instead of plastic hub caps, backup camera, unique body design, good gas mileage.
The only improvements I can think of will be solved by upgrading from the base Sport trim level to Touring trim level. For me this would be Bose stereo, Xenon HID headlights and 19 instead of 17 inch rims.