I picked Beer Maiden, only because if you are going to need an SM it'll proabably give you a tighter, sexier fit. But looks-wise I like the Beer Gal more. I'm just not sure it's going to give you the fit you want since it's a "One Size Fits Most" costume.
The first one is actually sized, and the second one is one size fits most. Based on that alone, I'd choose the first one, though the second one is nice in appearance, too.