Gio is a lot more like a real starter than Powell, and on a much better offense. I wouldn't base much on matchups Week 1, especially when Chicago has changed to a very different kind of head coach.
I'd go Gio as well. Powell should get some run, maybe even in the wildcat, and definitely in passing situations... but it's the Jets. I would expect Gio to at least split carries with BJGE this week, until the Bengals realize that will not get it done, and place Ben Jarvis "firmly" on the bench.