The stream is a lot more cluttered than Facebook. As an example, this is what I see next to a name in the stream:
Fname Lname - 4:17 PM - Mobile - Public
Compared to Facebook:
Fname Lname
There are lots of such details that facebook has right--mostly because they have been around a lot longer. I am sure Google Plus will eventually get it right(facebook's very first design really sucked, too).
Another example: when someone posts a picture, it seems to appear pretty big versus Facebook. It's an issue for me because most often I am not interested in pictures in my feed so a smaller version--like facebook--is preferred. If it looks like something of interest, I'll click on it.
When I do click on a picture in my stream, I am taken to a page with black background with all comments appearing on right in white/gray. It shows the non-standard nature of the Google UI which I personally dislike.
Facebook's UI may be boring. But most things I use a lot are boring and non-shiney.
All this comes from someone who really, really hates facebook for purposely holding back privacy features. I have pretty much resorted to not posting anything that may be offensive to a 5 year old kid.