Runs. They run a lot of spread. Zach was able to show off more than Lawrence did like going under center, reading a defense, not just throwing to the hot-route, etc. I could see Zach maybe being more effective in the early years because his jump won't be as extreme and then as Lawrence catches up to whatever playbook he is running his more God-given size and ability take over.
Who knows though. It is all kind of a guess at this point.