I have a Vitamix... and I use it all the time to make heaps of different things, the main difference is the thermomix actually has a heating component, where the vitamix uses the speed of the blades to heat up the food. So its just friction (sp?) that causes food to heat up, after 1 minute the food heats up 10 degrees every minute.... it is supposed to do the same sort of things but the thermomix can do more like what Alan said, although I can do doughs etc.... and scrambled eggs.

I use it alot for hiding vegetables from the kids, and making food that is generally more healthy... i.e. I make sorbets with 2 pieces of fruit and ice. So no sugar or anything else.... and the lime slushies (aka Margaritas) are lovely!