I am not an expert on the science of DB's and Barbell, but I do know that I get a 150% better pump using DB's than I do using a Barbell. I like DB's, they make me feel like I have worked harder. I do at least 3x8 of DB flat press on every chest to keep the stabalizers strong, and help with shape. They will not make you stronger than using Barbells, but I truely believe that DB's are far superior for shaping your chest.
Josh