I too was interested in a Complete > to Infinite upgrade and was more than surpised at E-ons response that there is none. As you say, until you've tried the program you don't know what you will need . The one thing I intensely dislike with Complete is the default start up screen with the difference in camera angle from VUE6 I  I know it is no great thing to do to create your own start up screen LOL!!!!  But why is it different?????? Makes absolutely no sense.

Oh, let the sun beat down upon my face. I am a traveler of both time and space ....Kashmir, Led Zeppelin