I have met Mark Fields once, at an industry event, a few years ago, during his "Bold Moves" effort. I only spoke to him very briefly, but from his demeanor I got the impression that he is a very bright guy, very driven, and a bit cocky. I also have the sense that he has an aggressive, competitive edge to him, more of a "hard charger" than you see from Alan Mulally.
I think Mark Fields will serve Ford well. He was partly responsible for the Ford Fusion, which helped save the company, product-wise, in the late 2000's.
I was surprised to see that Farley was put in charge of Lincoln as well as Marketing and Sales. It seems like a really big job--both global marketing for Ford and running the Lincoln brand are huge jobs. I hope he can pull it off, because Lincoln really needs help.