Like I said earlier. You are going to the exact same place each month. I have used hotelsdotcom in the past and Comfort/Sleep and those types kept coming up at $65-$75 a night. All were nice newer (or at least newly re-done) properties. I joined their rewards program and went from stay 10 get 1 free with Hotelsdotcom to stay 2 get one free with their rewards program.
Again. Pick the hotel that you have been to there in Atlanta in the past and go with that one. They may not have a corporate rewards program, but if you call them direct and explain that we will be the x# of nights each month for y# months, and you want the same room (#z) that you had last time you were there.