I'm perpetually between sizes.  If it existed, I'd be a 33B+/C-.  The medium fit me well, but I have no idea how the D+ gals fit into the medium (based on the tag's size chart).  It's not particularly supportive, but I wasn't looking for a sports bra.  I was looking for a comfy weekend bra that didn't have a uniboob effect.  I'm totally happy with this purchase.