Please note that the two substances are not even remotely comparable.
One is a drug that has been tested by the FDA, found to be effective, and safe.
The other has faced a class action lawsuit regarding its efficacy and has had a large number of negative side effects reported with its usage.
While I do not suggest making medical decisions based on what you read on wikipedia, it does have links to numerous articles on the topic: http://en.wikipedia.org/wiki/Extenze