Not looking to join the fray just offering another, hopefully objective, view.
I like them both, for different reasons.
I get it with the Tennessee Aquarium. I read the vision of the designer. The idea was to incorporate the various ecosystems/habitats in sequence from river source, down the Tennessee river, through Nickajack Lake, to it's destination at the Gulf of Mexico. I think they did a superb job in doing that, and in unique fashion. I particularly like the otter & jelly display/habitats, as well as both the fresh and saltwater main displays.
The Georgia Aquarium is obviously massive (gross understatement). They also incorporate different species/environments, albeit in not as systematic fashion. That being said, the main display window (whale sharks) is simply stunning! I would like for the reef wall to be a little more populated with corals, but honestly have not seen it for over a year, so maybe it is now.
I have seen many public Aquariums, including the- Shedd, Monterey, Steinhardt, New England, Florida to name a few. Both the Georgia and Tennesee Aquariums are in my top 5, and I feel incredibly fortunate to be living within 1 1/2 hours of them both! I don't have to, nor do I want to, choose between them.
Many thanks and cudo's to the staff's of both facilities.