Forum Moderators: Robert Charlton & goodroi
There is no predicatable behavior on duplicate pages that I've seen. Sometimes the fresher page does take over, but lots of other factors play in besides freshness and PR, and what page gets prominence is far from a certainty. Page Rank may be one of the determining factors, but age of the domain itself also seems to play in, as well as inbound link text, how many duplicates exist in all, etc, etc.
If you've read some of the many posts here about dupe content and also about scraper sites, you have some sense of how knotty it all is - black or white answers are hard to come by.