"Y Sabes Bien" is a fantastic song. Honestly, I'm not a big of a fan of doo-wop, but I find Los Zafiros' vocal harmonies utterly captivating, and the underlying rhythms make the music compelling for me in a way that doo-wop has never been. That and Manuel Galbán is an absolute genius on the fretboard. Oh yeah, and this video is amazing.
Los Zafiros first came on my radar after I picked up Ry Cooder and Manuel Galbán's fantastic 2003 collaboration Mambo Sinuendo. Many of Los Zafiros' biggest hits are collected on the 1999 Nonesuch compilation, Bossa Cubana. I highly recommend both albums.