Sigma has beaten the competition in being the first third-party lens maker to offer a native, mirrorless-optimized full-frame super-telephoto zoom for Sony's E-mount, and at just $950 it is a very attractive alternative to its name-brand competitor.
Impressive image quality, High-quality build, Fast, reliable autofocus, Portable size (for the zoom range), Incredible overall value
Tripod collar/foot is an additional expense, Zoom & focus rings switched position, Vignetting correction not perfect, requires additional help & causes faint color shift