Don't like it at all,
- Moves the page when someone posts such that you dont press the right button/link (that was really annoying) Or the reply/edit box disapperas of screen so you cant see what your doing
- After a little while your posts dont appear, even though every one else can see them
- Thanks buttons doesnt exist on posts which appear after the page has first loaded
I think its good to have some way of the thread keeping itself up to date, or knowing that someone has posted between when you click on the page and click post reply, I just didnt feel it worked that well.
Personally I think that its a cool feature that after a while, people will loose interest and find it more of an annoyance than asset.