I just made the switch over to Wordpress as a basic system to manage some articles on my site, (buying guides, projects, blog). Using Wordpress over Expression Engine is like a breath of fresh air. For my specific purposes, it is so much easier to use.
With Expression Engine you are starting with a blank canvas, and you have to go through and create everything. This may be great for certain sites, but for me, I love Wordpress in that it has everything pretty much ready to go, and you just spend some time configuring as needed. The template structure is nice, and love that you can override theme pages or the look and feel via the css.
One feature that's especially nice is how it places every possible type of value in the body class, in order to really fine tune the look with CSS without needing to edit the actual template.
I know there are somethings that Expression Engine is better than Wordpress, but for me, it is so much fun to work with Wordpress. I like the admin screen a lot too.
The other downside of Expression Engine is that you have to purchase so many extra addons for basic functionality. Such as WYSIWIG editors, tagging, permalink structures.