Jacare, Jacare, JA-CARE!
I've seen them in a bunch of grappling contests over the years and Jacare outclasses Jake by far. I think at the moment, Jacare's striking is probably the "crisper" of the two and would leave me to give him the edge in both submission/grappling and standup, however Shields has a fucking gastank and could really keep this one going if he could avoid the submission, although I'm not terribly confident that he'd be able to since Jacare's such a BJJ wizard.
I think that Jacare's rise within Strikefarce's MW contention was probably a pretty solid argument for Shields to travel to the UFC, because on paper at least, I feel Jacare trumps Shields in almost all of his own "wheelhouse" areas. Not a knock whatsoever on Shields, I just think Jacare(who I'm a total mark for) simply has a superior similar skillset and would benefit likewise.
Jacare via convincing submission Rd. 2.
MY MMA RANKINGS
HW Velasquez Cigano Werdum Cormier Bigfoot Barnett Mir Browne
LHW Jones Machida Evans Hendo Davis Goose Teixeira Shogun Mousasi Bader
MW ASilva Rockhold Belfort Weidman Jacare Okami Kennedy Consta Belcher Boetsch
WW GSP Hendricks Condit MacDonald Diaz Maia Fitch Kampmann Ellenberger Pyle
LW Bendo Alvarez Maynard Melendez Thomson J.Miller Diaz Pettis Chandler Grant dos Anjos
FW Aldo Mendes Curran Lamas Frankie Zombie
BW Cruz Barao Fernandes Faber Moraes