I have always worn a 40C underwire and been quite comfortable.  After breast cancer and lymph surgery, an underwire was no longer possible.  This gives me the support under the arms and a farily decent profile.  The wide straps assist with lymphedema prevetion, and the wide band around the midriff has yet to roll.  It does smash the girls together a bit, but perhaps a larger cup size would help.  So far, none of the bra shws under my scoop neck or v-neck shirts.  Highly recommended.