FF has not completed proof of concept, prototype or design phase so I would say there is a lot of uncertainty about the final pricing. It looks promising, but its far from done. Validation is an even bigger story.
I worked on several mediums size projects, and can say for certain that any journey looks easy before getting up.
Dennis, assuming FF does work as promised and pretty much on schedule, it will still require NRC type certification since the reaction is at the nucleus level AND because it makes X-rays. Couple that with the ability to derail some gigantic gravy trains, and the engineering challenges pale in comparison to the political challenges. In my opinion, anyway.