Go reread post #5.

I haven't stayed there but I do live near there and the "downtown" Renaissance is best avoided for what you are looking for. The immediate area gets pretty creepy at night.

I will third the recommendation for the Marriott Suites on 14th St. There is also a Residence Inn in Midtown on Peachtree St. that is a good location.

Without a car, I would stick to the Midtown area for walking access to both restaurants and nightlife. The Arts Center Marta station can get you to the shuttle that goes to the stadium and the airport.

I hope you enjoy your visit. The Atlanta weather in April can be changeable, but if it is a nice day in April, it will be a d@mn nice day.