This sucks.
It eats up too much space at the top of the screen, presents information I don't need to see every minute (rep and badges, which I could already see in the page header), badge progress (which if I cared about seeing, I could see in my profile), and watched tags (which were fine where they were on the right sidebar), but only a small subset of the tags I watch. (I can't figure out the logic used to determine that subset, either. At least one of them is a tag that almost never sees any activity, and it's among whatever random tags were selected.)
It also seems to filter questions out that I didn't choose to have filtered out. We had the ignored tags functionality for that purpose.
I don't see a single thing that this UI change improves, and a whole lot that it spoils. The first thing I did when I saw it had been rolled out was to go to the Settings in my profile to see if it could be disabled, and was extremely disappointed (read that as pissed off) that I couldn't.