Take Cover: Katy Perry's 'Wide Awake'

YouTube Channel: ddbail2

Cleanly presented with live audio rather than lip synched, the Bailey sisters – Chloe, 13, on keys and Halle, 12, on acoustic guitar – offer a beautiful and mature rendition, with the kind of smooth harmonies you can only get with a sibling. They occasionally push too hard or over-emote, but they are better rehearsed for this clip than some of their previous ones, and seem to be growing in confidence as they refine their performances. Among YouTubers, the Bailey sisters are worth paying attention to: Their video version of Beyonce's "Love On Top" nabbed more than two million views, and they were even invited to appear on Ellen last fall.

Presentation: B+

Performance: A