I would go with Jefferson as well. It's an established, well-known medical school with a huge alumni network as well. It's got more proven success than the new CUSM. Also, it's possible that Jefferson's match list doesn't include as many California programs because of student self-selection in terms of which geographic regions they'd like to go to. I'm sure since you have family in California and a desire to return to Cali, you can still match into California from Jefferson.