American Sniper is as divisive as Red and Blue America. Theory of Everything was a Theory of Nothing. And Inherent Vice was a generally considered Incomprehensible Vice. It's a two pony race between The Imitation Game and Whiplash.
The Imitation Game is a masterclass in theme. The three timelines are wonderfully interwoven, leading to the final question: What truths are worth uncovering? Turing's evolution is brilliantly crafted. The only knocks would be the dialog generally lacks subtext, and the moments where the plot lacks subtlety. But considering you have a reliable narrator in Turing himself, the lack of subtext and subtlety feel more like a writer's choice, rather than a mistake.
Whiplash is a terrific read, but structurally, it is a simple sports movie set in a unique world. The characters' motivations were as familiar as the structure. What sets Whiplash apart from most sports scripts is, of course, the "sport" is jazz drumming. I was engaged and intensely interested through the necessarily long descriptions of a world I didn't know. And like all good sports movies, the desired ending is never in doubt. To be honest, the ending on the page could never compare to experiencing it on screen. What a rush! Alas, this is about what is on the page.
Two very good scripts, no doubt. However, The Imitation Game gets my vote because it has a higher degree of difficulty.