A bunch of nonsense. All kinds of spiffy Web 2.0 animation and whatnot, everything slithers and slides, but it's just a new skin. I haven't noticed any functional changes.
One bizarre detail. With my particular web browser, OS, screen size, etc. etc. the old size consistently used fonts that were uncomfortably small. Now it consistently uses fonts that are uncomfortably large.
I do believe there's a bug in the text editor that causes it to mess up if you paste styled text into the editor instead of just typing it in. When I get it characterized better I'll report it.
Maybe the new site works better on phones or small tablets. I don't know.
I couldn't really care less one way or another. I am, however, very very disappointed that they couldn't come up with a way for users to edit or delete postings after they are posted. I make lots of typographical errors and for whatever reason I just don't catch them all until it's too late.