Like the Moller Air Car, to me this looks like a device designed to lift wallets from investors, not to lift people for actual useful purpose. Although I'm not a trained aero or propulsion engineer, I have a rudimentary grasp. In order to make something like this work reliably and efficiently without a LOT of thrust, you need much larger diameter rotors and a significant power reserve. Putting the fan in a duct is all well and good and sexy looking, but there is simply no substitute for aspect ratio and surface area in low speed aerodynamics.
Glenn Martin has done a remarkable and respectable job getting something to fly with a reasonable authority. In my book he has much more credibility than Paul Moller. But Martin's Fan Pack is such a limited and risky proposition.
Those who have not watched this sort of stuff for years and years might not be aware of some of the other and better efforts in this field... the Williams Wasp "flying garbage can" which actually flew very well
http://www.youtube.com/watch?v=XJARrc40imkor the Hiller Flying Platform
http://www.youtube.com/watch?v=C_UtPmb3Z-o If you want to make something like Martin's device really work, you're looking at something with the diameter of an airplane propeller with multiple blades. The little backpack helicopters (with all their issues and problems) are closer to filling this niche than the fan thingie is IMHO . If you're looking at one-man "personal VTOL flight", a smaller man-sized version of that huge new Lockheed cargo blimp/thrust monster might be a good start. Using a balloon of some sort to reduce 2/3 of the weight makes it a lot easier, and yet smaller than a full sized LTA balloon.