I'll try it for a bit, but I can't say I find it too appealing right now. We'll see though, change always seems quite meh at first.
As a bit of feedback, I think I prefer the usernames being above the posts really. Interested to see what happens when a user with a long name posts, whether it'll stretch the side bit or go onto a new line. There's just a big, white, empty space where that part used to be, seems odd to have that. There's also a big, white space to the side of my post, too.
EDIT: Okay, I don't like it, switching back now.