Blog Post
On a positive note: I like that the reply box grows to fit in what you are typing. On the previous forum it remained a tiny box with scroll bars unless you manually dragged it bigger.
Negative note: youtube video embedding is gone. All previously embedded videos are still in the forum and work ok, but it's not possible to embed new ones.
The viewing/editing reply HTML button is gone from the reply toolbar. That was handy when the previous forum decided to format stuff wrong (like not allow typing after an image if you inserted the image at the bottom of a post). I don't know if it's not required anymore, but I used it a lot and already went to use it today (check on the youtube embed situation) and found it gone.