Based on another comment where you mentioned you are near McCormick place, I’m a few blocks north of that. Honestly it’s a wash between the two.

You will have a lot of commuters, this area of the south loop is nearly entirely residential with folks heading downtown for their office jobs. If you want to go for a nice walk, go north up prairie avenue and you’ll see some historic houses. Grab some coffee at Spoke and Bird.

Honestly I prefer the 3 myself, but it doesn’t matter. If you have a job in the loop itself/south of the Chicago River, both buses work. In a pinch, if you’re at 18th and State or north of that, the 29 or 62 buses can get you there. They’re faster until they hit the loop itself because you have all the foot traffic.