I taught dozens of people to use the VectorVest product. Over the years though, a trend emerged in terms of the feedback I was getting from them and these comments confirmed my own experience. People kept saying I have deployed a trading system but the results in the real world don't match the back test results... not even close. Hence, I undertook a process of auditing the trade reports generated from back tests by comparing the reported trades against the settings used. The outcome was that the trade sizes did not match the settings in the back tester. This finding led to more in depth testing, and the uncovering of a raft of other problems in the back tester.
Because VectorVest chose to ignore these problems when I reported them, I had no choice but to end my subscription and not teach the product anymore.
Also, if you are considering VectorVest you should read this http://kaner.com/pdfs/fitInvestmentColloquium.pdf its old but still relevant