Karmin is by far, in my opinion, the best cover band on youtube. You may have come across their version of 'Look at me Now' by Chris brown, which has shot them to stardom and led them to sign a record deal with LA Reid's label. However, my favorite Karmin cover is of Nicki Minaj's "SuperBass', first due to Amy's amazing vocals, and second, for the surprise guests that show up halfway into the video clip.

Enjoy!