Comparison Pictures:
Because a picture is worth a thousand words, I thought I would show the raw results of each keyer on some footage. Rather than just testing it on optimal footage, we tested each keyer on both professional footage (both it and the background were kindly provided by Elsevier & Post-Holes from John Jackman's new book, Bluescreen Compositing) and problematic footage (which was specially shot by us to have logical issues without going insane).
First, we tested what I’ll call the “One-click” key, which is, in fact, a two click key. (Most keyers require at least two sample points to do a key, with the exception of Keylight and Primatte, which both require one, and zMatte, which simply selects a matte color.) This basically shows how each keyer does with the minimal amount of color data and no further adjustments. First the problematic footage and then the professional footage.