AGGER vs. SKRTEL: Who is Liverpool's best central defender right now...?

Daniel Agger and Martin Skrtel have forged a fantastic central defensive partnership over the last couple of months, but who is currently playing the best out of the two?Like most great defensive partnerships, Agger and Skrtel complement each other very well. Skrtel is the Carra/Lawrenson-esque 'last-ditch' scrapper, whereas Agger is the more elegant, Hansen-esque ball-player.