Mick Jagger is getting positive reviews from the public for his efforts on "Saturday Night Live." The Rolling Stones frontman served as both the host and musical guest for the season finale of the NBC sketch comedy show, which aired over the weekend.  Sixty-percent of the respondents in an AccessHollywood.com poll say Jagger "nailed it!" A quarter of those polled say Mick was "just OK," while only 15-percent feel he "missed the mark."  Jagger took on many characters for the show, including a critical insurance conference attendee; a game show contestant; a soap family patriarch; and Aerosmith's Steven Tyler.  He also performed with Foo Fighters and Arcade Fire, and caused a stir by including an obscenity in a song with Jeff Beck that poked fun at Republican presidential hopeful Mitt Romney.