Des Moines - In the final Des Moines Register/Bloomberg poll, Donald Trump leads the field at 28 percent with Ted Cruz in second place at 23 percent and Marco Rubio in third at 15 percent.What's remarkable is that Trump is leading despite fact that's he's a deeply polarizing figure among Republicans: Nearly half of likely caucusgoers (47 percent) view him unfavorably, while 50 percent view him favorably. Trump's +3 favorability rating is well behind the favorability ratings of Ben Carson (+50), Marco Rubio (+49), and Ted Cruz (+37). Polling analysts note this is highly unusual:..."It makes you scratch your head,"...