Having watched both Cooley(in Turkish league) and Motum(in Fiba Cup) I'd give the edge to Cooley. He's simply much stronger than Motum and that would help greatly for translating his traits to the NBA. He's also a smart player on the court.
I liked Motum a lot in the Fiba Cup too, though. He's a calm and consistent presence on the court, has a feel for the game. But nevertheless, they are both limited players in terms of their upsides which is being a good bench big and role player at their peeks. Still, they will be very useful for the Jazz rotation, practices and all. Plus they look like good guys, so it's going to be good for the team chemistry too.