What I loved about Clinton's speech was that he didn't just come out there and play cheerleader to rouse the crowd. He could have been very successful simply by doing that.
Instead, he laid out the stark contrast in policy objectives between the two parties in language that ordinary Americans, who don't pay that much attention to politics, could easily comprehend. He then revealed, in no uncertain terms, the historical results of pursuing these opposing policy initiatives.
He made a solid case as if he were in courtroom, yet he managed to keep his audience from tuning out from sheer policy-wonk boredom. Not many public speakers can pull that off.
Bill Clinton absolutely dismantled every argument that the Romney/Ryan ticket has made during this campaign. He made them look like the sophomore pikers that they actually are.