When negotiating a project in the private world (not municipal) it seems very self evident that design build with an amendment price is the best for all parties. The customer can designate a fixed cost and its up to the design build agent to hit the target or the project will never be constructed. The risk is shared. Honor and trust is required by both, a true partnership. It is amazing that any sound minded professional would believe a hard bid will result in the best possible final price. Any qualified GC or CM will pad their cost accordingly to protect their interests and buffer the costs as resultant of design problems that were outside of their control. This is why we see more and more qualified GC's and CM's not participating in a hard bid process anymore. It makes sense the hard bid method is preferred in the municipal world. Clearly they do not value their customers (tax payers) or project cost. Change orders are a prerequisite. Just remember, in a hard bid scenario low bid is only low bid until the project begins.
Design Build by Pelletier Construction Management