Usability issues
 

So many usability issues.

Search:
Well, you know. I can't even save which tab should be the default for me. I'm not interested in CMS.

Show Results as posts:
It's better not to show anything of the posts without slow and systematic process?

Truncating thread titles:
I shouldn't have to read friendly URLs from my browser's frame but I haven't figured out any other way to read the whole titles.

Navigation:
Quick Links has 4 items now... Sometimes you have Community, Quick Links etc. at the top, sometimes Quick Navigation at the bottom, sometimes both, sometimes neither. Nowadays I tend to keep two tabs open to avoid detours at forum index or other pages.

Overall efficiency:
Vb3: click, click, click
Vb4: click, click, click, click, click, click

I know it's a new product and should look fresh, but please consider the practical aspects more. Creating bug reports about changes that don't have any apparent benefits is frustrating.