Let me begin by saying this bra works great for me but may not work for you. I'd advise anyone considering a purchase to see if you can try one on at a store (like Von Maur or Nordstrom, who do carry them) first.

That said, I am a 34B and a size 4. But even I get the dreaded "back-fat" from regular bras. I had even stopped wearing t-shirts for the most part because of my back-rolls. This bra has solved that.

I ordered a 34B and it fits great. I have not had a problem with the cups rolling over, straps sliding off or the back riding up. I do notice that the stretchy material can loosen up after a few wears, but it has not affected the comfort of the bra. Aside from that, it shrinks back to the normal fit after washing. If you are going to wear this bra every day, I would recommend buying 2 so that once one stretches, you can wear the other in between washings.

The best aspect is that I have no more back-rolls. I wear t-shirts---even snug, white ones---without worry.

Negatives? I would say that the only one for me is that the straps are wide, so you cannot wear this bra under a tank-top because they show through. Bummer.

I also recommended this bra to my mother who just underwent breast cancer surgery. She is obviously looking for a comfortable bra and liked this one so much she bought two. She is a 34C and bought her regular size.