The only hotel actually in Atlantic Station is the Twelve hotel. The rest of the hotels people have mentioned ( Lowes, 4 seasons) are close to the 14th and Peachtree intersection so you would either have to drive to atlantic station or take the bus from art center. I would also add the W Hotel at colony square to this list.
For what it is worth, I have had a good experience staying at 12 and I have also been to an after party in a hotel room there after my work holiday party. We were told to be quite by the hotel. Not fun when you are a party goer but good when you are the other guests.