I don't like the design at all, it looks so boring, the blue top bar is ugly! Their old design was nice, I loved it, at least they could have shrink the top bar from the old design instead of implementing this one. No modern UI design, I won't comment on fluidity because I don't see one, in comparison with the people hub this works kinda slow.
It's good that they work on fb app, but unfortunately on the design part it is in the wrong direction.
What I noticed in my short experience with the beta app is that:
-at first no news feed, had to go to settings of news feed to show what is recent, doesn't know top stories.
-at chat, when you go on the typing area, the pulling of the screen upwards is laggy
-pictures load in more than 2 seconds (and trust me I have a good connection).
-when you look at a picture in landscape mode it will show on the side of the screen a part of "favorites people"
Pretty much that's it, I uninstalled it, my principle is that I don't use apps that I don't like how they look

Anyway, before this beta I wasn't even using fb app, the people hub is enough for me.