I guess this depends on what you're trying to get out of the experience. If the goal is mainly to beef up your application, then I would probably pick Amgen as the name, social connections at with faculty and peers, etc. are valuable. It's great that the second option may make you more likely to publish but like @eteshoe said, publications are not guaranteed, and even if you get the data for one, timelines are often uncertain. The other factor I would consider is how good of a mentor the PIs are, if you have any insight on that, and which research topics you are more interested in.