Unpopular opinion ahead:
I kinda like the new DA UI.
At first I was like "EWWWW" and "WHAT THE FUCK?!" I was afraid they deleted the old message-center. But it's still there. So my first fright was solved. And I have to admit, I actually like that all the messages are on the top right now. It's just ... dunno. I just like it. (maybe that's because my mouse weel is broken, and I have to go to the sitebar with my cursor anyway)
But the feeds need more work, in my opinion. The idea is nice, but it's strange to use.
The Watch Feed is like a Tumblr-Dashboard and as on Tumblr, it's just a mess.
But on the other hand, I really enjoy how easy it is now to write comments in the Feed...I see the picture big enough and I can write away without clicking on it. Megusta.
The only thing that pissed me of was the "Activity Widget" on my Profil. Deleted it right away *shrugs*
So yeah. Didn't take me long to get used to it, even if i hated it at first.