It's pretty neat! Took a moment to figure out how to create them. I've gone through and added four, at least, to help organize a few things. I'm glad it's in, though it's never something I complained for.

As for the Beta itself, I say it's shaping up pretty well. I know folks like to complain and such, but I think if they take a few days to really just soak it all in, it's a lot better looking than classic. Perhaps a touch more functional as well. At least to me. And you can see changes, usually every day or two. Little tweaks here and there that help improve functionality and viewing. I'm pretty glad that  dragoneer has more time to sit down and actually work on the site.

Improvement is A+!

Of course this is all my opinion. Your mileage may vary!