Sigma 20-60mm f2.8-4 Contemporary Review: How is This Lens This Good?

The Sigma 20-60mm f2.8-4 Contemporary lens has to be one of the nicest and sharpest zoom lenses of it's kind that I've ever used. And the only thing that could've made it better is fuller weather resistance. "the vibes of the 20-60 with your processing makes me feel the brightness and heat of a NYC summer," is what a friend told me when he looked at images from this lens. Really, I think this lens is better served for Leica L-mount than it is for Sony's E-mount that value...