Are underwire bandeau bras any use??? 10pts?

I wear a lot of strapless and off shoulder tops during the summer, and I HATE bra straps showing. Strapless bras always slide down, I bought an elasticated bandeau and it made my boobs look saggy! So are the underwire ones any good? Like this one: a href="http://www.asos.com/Princesse-Tam-Tam/Princesse-Tam-Tam-Lucky-Underwired-Bandeau-Bra/Prod/pgeproduct.aspx?iid=1500098&sgid=2467&SearchQuery=bandeau%20bra&sh=0&pge=0&pgesize=20&sort=-1&clr=3062MarcelloBlue" rel="nofollow"http://www.asos.com/Princesse-Tam-Tam/Pr…/a