Several former UFC fighters that switched over to Bellator spoke about their reasons for moving during free agency. Guys such as Ben Henderson, Phil Davis, and Josh Thomson cited a lack of actual negotiation, the Reebok deal limiting their income, and non-guaranteed backroom bonuses.
Among the many issues detailed, was a story about an argument Matt Mitrione had with UFC CEO Lorenzo Fertitta as his contract was ending. Here's how Bleacher Report had it:
The two sides had been engaged in a discussion regarding issues related to the Reebok sponsorship deal when the fighter tried to punctuate his point by reminding the executive that the 500-plus fighters on the roster are the UFC's product.