I decided to buy this top w/ the skirt instead of the dress, and I made the right decision!  Getting it on, youll definitely need someone to help, but thats it.  I ordered a small and I am 59, 115lbs, and a DD Cup for reference.  The straps stay in place, and around the top, there is a silicone lining to prevent it from slipping down.  The material is definitely high quality, (like material from Bebe or BCBG)