The Sing Off heads into tonight’s season finale with four A Capella groups vying for a $100,000 prize and Sony recording contract. After singing superstar medleys in last episode’s first round, On the Rocks struck out with an Elton John set. They had all the flash, but maybe no real singing superstar to make the cut. I wasn’t personally in love with The Backbeats and their Gaga medley, but that’s because there’s just something about them that just doesn’t click with me and I can’t put my finger on it. Just a little bit like I’m watching a grown up version of Kids, Incorporated. Committed was flawless with an Usher medley, even if they don’t have the breakthrough choreography and Street Corner Symphony did an enjoyable and interestingly arranged Beatles medley that built slowly to a strong finish. Oh yes, and Jerry Lawson & Talk of the Town wailed on Otis Redding’s finest, which may not have been a shocker at all, but they just have the polish and class that comes with experience to really sell it.