Duplicate content can tell Google your site dont have much good new things to offer, you have low chance having good position in google search results (SERP), when publishing usefull and unique content i think your chances can be higher.
I think one should base all SEO works like linkbuilding only on site with unique content. Moreover linkbuilding must be made very natural way and never in bulk.
content is the king of SEO. By posting unique content you will get unique backlinks as well as increase website traffic which will rank your targeted keywords within a short period of time by search engine.