Greenwood is obviously an artist of some scope and skill. He has an extensive portfolio to browse through. He self curated a section called most recent which I used as the launching point from which to examine his current state as an artist. I find his work to be expressive and clear.
Oddly enough the pieces of his I like the most are ones that with a less skilled artist I would put in the category of graphic design but Greenwood has done so well and with such balanced that I choose to call them art. Killing the Emporers is the best case of this though all of his mystery novel covers are equally pleasing.
His science fiction covers are classic: Battle School & Shadows in Flight. His fantasy covers also deliver: Shadows in the Night & Notes on a Page. Everything is well balanced both by visual weight and in colors and he is very true to whatever genre he is illustrating: Oggrak.
A solid showing and definitely a professional artist.