I just joined the beta today and the first thing I noticed was how much I have to click and scroll!
Because images and the first few lines are shown in the view there's a lot of scrolling just to get through a few posts, even when I'm not reading them! Given the condensed number of forums/categories/sections I think scrolling through new posts is going to get very laborious, I feel my RSI symptoms screaming just at the thought! 
When I click more on a post I'd like to see the replies expanded at the same time rather than make it another click, after all, I said I wanted more than just the summary so why not give me it all?
I have a pretty wide screen and the width of the post list doesn't appear to scale to take advantage of this so I have a narrow section in the middle with the content in it but lots of whitespace on either side, could the window width be used to dynamically scale the content?
Just my first few impressions, I'll give more feedback as I get used to the change
Cheers!
HW