Seeing as how congress wanted to push the development of a heavy lift rocket to 2011 instead of the 2015 date that Obama had put forth this past tax day, then I say give them a shot. If Lockheed can produce a HLV before Boeing can, then Lockheed is the company we should go with. If NASA can come up with a system of checks and double checks before doling out money, than NASA can minimize it's risk to an acceptable degree. This will be accomplished by NASA either giving the go ahead with as much assurance as possible that the mission will succeed, or NASA will decide that Boeing is the better option. So I say go ahead, give the home team a shot, see if they've got what it takes.