I got them when I outgrew my usual size, since at that point you need a new bra that fits anyway, so why not go maternity? They have far more hooks in the back than regular bras and are more comfortable, but they don't exactly perk you into a flattering shape.

Then I grew more and got more, more, more more and more and now have every cup size from D to I. And I'm not kidding. I have at most 2 of any size but that's just because in the larger sizes they cost around $100 so its a budget thing.