I also own DD, and i have to tell you my initial thoughts after i received it were about the same as yours. anyway, after some practicing i tried it, only with my family at first, and it worked, but not 100%. After that I did some fine tuning and found that it works perfectly.
there are just some minor points that should've been on the DVD in my opinion (although it's not really revealing i'll send you my thoughts via pm). after all, i think it's a very good effect and definitely worth the money ;-)