I love wordpress. I'm using it for a dozen sites and switched long ago from other CMS installs. I am very grateful for the software and the development and support community. Although no one likes a whiner, I've come to complain about 2.7
I hate the change to side navigation. This is a huge adjustment and no longer a user friendly interface. My important plug-ins such as NextGen and Statpress now are found at the very bottom of the left side.
I'll get over it because I have to... but I chose not to upgrade my other sites after experiencing the "upgrade" on two sites.
Again, it's hard to complain when I appreciate the work so entirely but this new interface blows.