Definitely casual/American. I enjoy going to restaurants or getting food that is unique to that area. For example Louisville is known for their Hot Browns so I go somewhere there that's known for those sandwiches. Budget wise - not looking for a Michelin Star place but doesn't need to be on the cheap. I generally don't eat large portions so that's why I tend to go more casual.
If you like Southern food, definitely check out Mary Mac's Tea Room. It's delicious and a classic Southern place.
Ponce City Market has a really exciting food hall, and my favorite stall there is Bibi. It's middle eastern food and the owner also owns a place called DelBar which was included in the Michelin guide and the food is almost the same.
We also are known for lemon pepper wings so be on the look out for those.
We have a whole area of town called Buford Highway which has lots of different styles of food if you are feeling adventurous. Excellent bang for your buck.
Roshambo is an American diner in Buckhead that is owned by a local restaurant group and I'm a big fan of what they've done there.
And finally, my favorite for sandwiches is either Publix for a PubSub (sooooo legit) or a local bakery called Henri's - love their chicken salad but honestly all the sandwiches are so good.
Atlanta is SUCH a food town so have the best time.
And as far as crime, just don't leave ANYTHING in your car and you'll be fine. Just like every other major city in America right now, car break-ins are way more common than they should be.
I used to work at the Avalon and it's so great, but if you are going to be hanging out in Midtown or south of the city, it's too far because it can be up to 90 minutes with traffic. You'll be okay at a hotel in Midtown.
