Upshaw.
Sullinger was expected to be a productive, useful NBA player, albeit one without a terribly high ceiling. He made an immediate impact as a rookie, but only played the first half of that season.
Upshaw might never be able to find his way into an NBA rotation, because guys like that have a tendency to alienate teammates and coaches alike due to personality, work ethic, or fitness issues. He might even get himself suspended, or decide that he doesn't really want to be a professional basketball player that badly.
It's always riskier to take the guy who might never contribute to your team over the guy who will almost certainly contribute, but not as consistently or reliably as somebody with a better health prognosis.