Yesterday, I upgraded to wordpress 2.7. Visitors would not notice a thing but it really is cool for the admin. The new wordpress has a more user friendly layout, althoug a bit confusing at first. It is easier to publish a new post now, and the new collapsable menues are very convenient and more user friendly. And all my old plugins and widgets work well with the new wordpress.
One thing that annoy me though is the overlapping of some elements in the user interface. I am using firefox and some elements overlap. I don’t know if this happens to IE users, but I hope it will be resolved in next version. Apart from this, I am completely happy with my new wordpress upgrade.