So many conflicting reviews!  I'm a 25yo C cup who likes high-intensity workouts with a lot of plyo.  I like my girls kept pretty tightly in place, which is why I went with the A/B cup bra (figured it'd be nice and tight).

Here's what I wish I'd known before purchasing:
1. It's THIN fabric.  There's no supportive padding or shaping/strong material to hold you in.  The reviewer who mentioned swimsuit top has it pretty right with the material.
  - I personally (again, C cup) won't be using it for anything involving running and jumping, but it's great for
  weights and spinning.
  - Also, if you like working out in just a sports bra, I wouldn't go with white (unless you don't mind
  your areola and nipples clearly outlined).

2. It IS compression fabric.  If you don't like being squeezed a bit or aren't used to UA compression fit, you probably won't like it.  I happen to love the tightness.  I suppose if you have a problem with uni-boob, you also might be displeased.

3. The commenter who mentioned Texas heat is absolutely right.  It stays pretty cool and does a great job wicking sweat away from you.

4. For the people who thought they were getting 2 bras, ehh... I think you should have read a bit more carefully rather than call the seller misleading.  Unless I'm very much mistaken, it's the UA Original #2 bra.  There's also the UA Original and UA Original #3.