We keep talking about how Broxton keeps making 9th innings interesting, so I took a look at Baseball Reference. Of Broxton's 24 appearances this year, he has allowed no base runners in 6 of them (though to be fair, there was one more where the only base runner was due to a fielding error). That means 25% of his appearances have been "clean."
By comparison, I looked at Soria's 2010 season (which was probably not even his best season despite it being his career high in saves). Of Soria's 66 appearances that season, 21 of them had no base runners (though I counted at least 3 that looked like the only base runner was due to a fielding error) - so 31.8% of Soria's 2010 appearances were "clean."
Unfortunately, I can't find this number summarized for all closers, which is what I'd really like to see in order to answer the question: Is Broxton really that bad about creating jams in the 9th, or are we just spoiled by Soria?