M.I.A. is an artist had a unique sound for American popular music. Despite that (or because of that), she got huge last year. I thought she was awful at Lollapalooza last year, but she did have a lot more people than the band she drowned out, Electric Six, playing on the stage next to her. Anyways, it seems that the major labels are trying to repeat that success with Santogold.
Santogold sounds like M.I.A., dancey music thats heavy on the beats. The music has a 80’s pop and a world music feel to it. She is is getting a lot of affection from the “blogosphere”, so you better get a listen in before the backlash starts. Give it a listen at HypeMachine or at Lollapalooza this summer.
Many music blogs tend to only focus on new music, ones that mainly focus on older music stand out. 
John Mayer’s like-ability factor goes fluctuates a lot. He does things that make me hate him like creating crappy adult contemporary songs, doing great blues stuff to get cred while still pumping out adult contemporary songs, and then theres the dating of Jessica Simpson. He gets points for actually being good at blues and every once in a while using it, being mostly entertaining whenever I have seen him interviewed, and being friends with people like Eric Clapton and Buddy Guy. Though the real question is if he is ejaculating or crapping when he makes faces like the one above.