Not all design-build project delivery is the same. There are Contractor-led Design-Build and there are Designer-Led Design Build. Generally speaking Contractors have a different set of priorities during construction when compared to designers or Architects. The Architect has an inate sense of the materials, detailing and design concepts. When the Architect is also the builder the seemless flow of information bleeds between the design phase and the construction phases. Needless to say an Architect who is also your contractor will work dilligently throughout your project to keep budget, schedule, concepts, materials, and detailing as high priorities from concptual design to final inspection and beyond.
Design-Build outperforms design-bid-build projects on a multitude of factors. More to come on this subject in the near future but for the moment here are the highlights: Reduced Risk, Higher Quality, Cost and Schedule.