Out of all the recommendations, I think I agree (especially after the fact) only with A.A. Bondy.
While the Whigs are undeniably great, Rodrigo y Gabriela's conflicting set absolutely destroyed EVERYTHING else at the Hangout. Grace Potter rocked out like nobody's business. I was very excited about OK GO, but their show absolutely sucked, sucked, sucked. And Zac Brown Band? I love real country music, but I couldn't listen to these guys for more than 10 minutes.