Not that Santorum has any room to talk about "bomb throwing", but he's 100% right on Ted Cruz and half right on Paul.
In the U.S. Senate, Rick Santorum led the fight to pass welfare reform, the ban on partial-birth abortion, and sanctions towards Iran. He was engaged in a variety of issues and was part of the GOP leadership. He also knew how to work across the political aisle.
Rand Paul lacks the judgement to be President of the United States, he has no accomplishments in the U.S. Senate other than managing to embarrass the GOP.