Please don't misunderstand my concern- in the proper hands, these can be delightlful and useful machines. The proper hands, by definition is someone who knows what they are doing, not just someone who thinks they know what they are doing.
You can't be mechanical in your flying technique for example - how do you learn not to be mechanical (and by that I mean "takeoff is defined as pulling up on the collective and waving the cyclic around and pushing in 3.2" of left pedal).
Having been peripherally involved in at least one of these devices, my first requirement for working with them was - you must set up a training school with experienced instructors who are not afraid to say no. Your reputation is on the line if you make a kit built helicopter. You must insist that your customers have at least a private pilot rating on helicopters before you sell them the kit.
Otherwise, you are risking your entire company on someone who doesn't really know what they are doing.
Rotorway, in the very beginning, had a book on how to teach yourself to fly a helicopter. They quite wisely withdrew the book.
If I could afford a light helicopter, I'd buy one - lots of advantages cost-wise.