Don't see why everyone thinks this is good news. For the sport and UFC to grow, they need more secondary organisations providing opportunities for fighters to prove themselves.
Strikeforce also can provide an opportunity for Zuffa to recruit promising talent that isn't quite UFC ready, have an alternative to totally dropping fighters totally from their roster, target a different audience segment (cheaper price point), and it gives them more media opportunities.
Having Strikeforce is better for Zuffa and the UFC in the long term from a fighter and fan perspective. This has to be a cost issue.