Carl Sagan has written at length about the limits of the credibility-assessing heuristic you're following. There's a reason that scientists have been snowed by paranormal fraudsters while professional magicians have not. I know nothing about D-Wave and have no opinion, but you need to look to people who manipulate people for a living—think the Amazing Randi—for accurate assessments of these sorts of things, not scientists. To paraphrase Sagan, the problem with scientists is that they are trained to fight against an opponent—Nature—that typically fights fair.