JGL operates in the uncanny valley of actors for me. (If you're not familiar with the uncanny valley, go here: http://en.wikipedia.org/wiki/Uncanny_valley
He's somewhere between an actor you can't believe and an actor you can. And it just puts this weird creepiness to his acting that I can't really put my finger on and makes it hard to watch him at times.
Gosling on the other hand, is brilliant. Drive, Ides of March, Lars and the Real Girl are all great. I'm quite excited to see his work in the future.