TheOne,
I can't comment on Ensign, but Amibroker is a powerful backtesting program that can do almost anything you want. The programming language takes some getting used to, however, so you'll have your work cut out for you. The system is really more appropriate for people with semi- to advanced-programming backgrounds, IMO.
Apparently, there is a plan to make it more user friendly, but that's for future upgrades.
From the Amibroker Yahoo forum, I gather it is one of the best systems on the market for running scans on baskets of stocks, but I've never used it for this purpose so I can't comment personally.
One good thing: the developer is on Yahoo practically every day answering questions and correcting people's coding attempts.
One bad thing: it is not configured at present to do automated order execution. Dynorder is said to be working on this.
Oh, and it's free to demo although the demo has limitations.
Hope this helps,
chaos