I only bought this bra for when I need a nude t-shirt bra, which luckily is not very often. The cups fit me fine, but the band is way too big even on the tightest hooks. Also I find that the straps don't adjust long enough for me if I use the racerback hook, which then makes the band ride up even more.
This is a pretty good standby which I've heard fits most shapes. The band and cups fit just as expected. I have a couple of different colors/designs of this and one does not gap at all, no matter what, while the other has minor gap when in certain positions. (I have shallow cups so this is always an issue to consider for me.) The only thing I do not like about this bra is that because it's a convert-to-racerback, they have the straps which only adjust half as much as usual. They still slide down even when tightened all the way for one of mine. The other one does ok when tightened all the way, but after it gets a bit stretched out I might try to alter the straps. The too-long strap problem is a common one based on the reviews on Aerie's site, I wish they would change that and then it would be perfect.
I really wanted to like this bra, it's comfortable and smooth but it's got a funny shape to the cup. The wires are quite long for a 34B and dig in at the top of the side a little. The band is really stretchy too, so if you're bigger than a C cup you probably won't find enough support from the band. I filled out the cup well but it is closed at the top a bit and it creates a small quad boob. For an unpadded bra it really projected my breasts nicely and captured every last bit of breast tissue in the cup, it just has a funny shape that I can't really explain, not pointy, nicely rounded but it's just off.