Its just that everything is cobbled up together. Too much stuff going on at the same time. Plus too many bright colors. Dunno, its just overwhelming for me. Maybe you can have a designer take a look at it and give you professional feedback?
Edit:
I guess my main issue is that the container holding the main content is too narrow. In SO you have about 70% of the page for the content. Here you have about 40%. Plus the font size is a bit small.
Also, the suggest edit VS comment thing is confusing.
Refresh the page, just widened the content, better?
> Also, the suggest edit VS comment thing is confusing.
Hrmm, well one is for editing the content, and the other is just for discussing it. I see how the UI for it is confusing though, I will brainstorm some better approaches to it.