I may be the odd man out on this, but I'll be brutally honest here and say I don't like it. The font is too... I dunno... squarish? Easy to read and sharper than what is in use now, so that is a plus at least. Actually I guess it's the same font, but a tad smaller and fully black rather than grayish? In any event, there's just too much of it everywhere. Or maybe I'm just distracted by it because there's so little in the way of color and graphical elements.
The logo... while updating it is certainly in order, the fonts used are very much boring. That may be the single worst change here.
The red-colored rows that indicate the section title, post count, etc, are perhaps a little too tall in relationship to the font size. Actually the fonts in those red bars seem inconsistent. At the very top, where it says Home, Forums, Articles, etc... that doesn't look too bad for the size. But below, it's either a different font or a smaller one, not sure which, and the letters look a bit too much mashed together.
Speaking of red... there's too much red. Perhaps the forum categories could be changed to a blue color... to match the > icons to the right of each. That would help offset the colors a bit. Or better yet... same color blue as the category titles (General Discussions, e.g.).
Compare the header for this post from the old and new site:
http://www.mac-forums.com/forums/ip...at-scratches-iphone-4s-glass.html#post1327708
http://stage.mac-forums.com/forums/...at-scratches-iphone-4s-glass.html#post1327708
On the new site, the background that was red and clearly differentiates one post from the next now is a rather like gray that sorta floats there. I do like the whole "shadow box" look for each post, but I think making the header graphic more solid would help break up what on first glance looks like, I dunno, a bunch of text floating on white background. It looks somewhat surreal, perhaps? Sorry... not sure how better to describe what I'm thinking here. Maybe pin striping just inside the border of each post would look good?
Anywho... those are my initial thoughts.
EDIT: What looks really good is up top... the stylized bar where the name/password fields are. That rocks. In fact, I think using that style, with the light gray background and white pinstripe border on top of the shadow should be implemented more throughout the forum, like for each posting to address the concerns I had. This would add more color (even if it is gray) and some graphical nicety to the whole look here, and some more consistency.