MSI Z97 Gaming 7 is better in every single way.
Gaming 7 has better component quality. Better capacitors, little bit more efficient powerpak mosfets (must be around 40A@6.5W) and it also has more mosfets than z97-A since it has more power phases.
Z97 Gaming 7 has better and more complex power regulation. z97A has 4 true phase vrm with a double (or virtual) driver and Asus renamed the controller in a very suspicious way. So noone knows it's actual manufacturer. They decided to hide it... But it's certain that it is not a higher-end digital controller from International Rectifier like last generation. It's just subpar and probably a hybrid... Z97 Gaming 7, on the other hand, has a 6 true phase hybrid/analog controller with a doubler driver from Intersil (so total of 12). MSI didn't want to hide what they use here.
Z97 Gaming 7 has way way way better sound chip and nichicon caps. Two mobos not even comparable in terms of sound quality.
Gaming 7 also has more sata, more usb etc..
Don't even think twice. MSI Gaming 7 is one of the best boards you can find in that price range. Even better than Asus Z97 Ranger.
Unless you can afford HERO, Gaming 7 is one of the best choices here. You also can check Gigabyte's Gaming series, which employs slightly better vrm than MSI's offerings.
Just stay away from ASRock, since they are just lying about their products, false marketing all around on their website...