I've been interested in the Virtual Intelligence Matrix project for quite a while. I wouldn't say that the demos are limited compared to the licensed versions; I think in most cases the most significant difference is the ability to save the state of the matrix.
My experience has been that the program is utterly fascinating for a while, and then becomes sort of boring. It's entirely visual at this point, with no use of language, and after a while one gets tired of seeing the (admittedly appealing) woman run around picking and planting flowers. I actually find the version in which she does cave paintings the most intriguing.
The boredom factor aside, the creator of this project (a PhD in neuroscience named Michael Colicos) seems truly committed to developing a revolutionary simulation of human cognitive and linguistic processes. He hasn't been very communicative lately, because, he says, he has been very busy both with his job and with the VIM project, but if you read some of his explanations and objectives on the site's message board, it's clear that he has a remarkable vision and a strong determination to achieve it. I hope he does, and I bought several licenses to support his efforts. Although I find it hard to believe he will actually manage to produce the results he seems to think he will, I'm convinced that he's sincere--and damned smart. Furthermore, he seems like a nice guy (I've corresponded with him a bit).