I chose to have a BA because of my very obvious disproportions. I was a size 12 pant size with a AA cup size. I felt like it would make me feel balanced and make me feel more feminine.
the Pros, I look more in proportion and I feel less critical of myself.
The cons, well there is a new fear of being in public in a swimsuit. I have had random people come and tell me that they can tell I've had a BA. Which is rude on their part but it did cause a bit if hesitation for me.