Some time ago I announced I was moving away from ExpressionEngine in favour of using a Tumblr blog. I chose to go down that route because I gave the site a design overhaul and decided I didn't need a full system to run it.
I figured I could set up a simple page and feed the blog directly from Tumblr. For a long time I enjoyed the simplicity of Tumblr especially after I discovered the Tumble iPhone app and could blog directly wherever I was. I still love the simple nature of the interface and still recommend it to friends and family when they want to get away from the Facebook and Myspace blogging systems, but for me it wasn't really enough and came to the conclusion that it was time to change.
I toyed with the idea of using TextPattern but having used it on a project recently, I found it hard to work with so it just wasn't for me. I turned my attention back to Expression Engine because I enjoyed using it the last time I built my site with it. This time around I devoted a bit more time reading up on the documentation so I have a better idea of what I'm doing this time around. I've still got a lot to learn but so far, I'm not doing to badly.
For me the great thing about Expression Engine, apart from the seemingly endless things you can do with it, is the interface through which you write content and manage your templates. Out of all the systems I've used it's by far the easiest to work with. The simple tab navigation makes it quick and easy to find your way around your site.
If I were to name one bad thing I've found so far, I wouldn't be able to. The only thing holding me back from achieving what I want is the limit of my knowledge. If I could ask for anything to improve the use of the system, it would be an iPhone app that allows me to post directly while on the move.
If you're looking to switch to another system, or even if you aren't looking, give EE a try. Hopefully you'll be as impressed as I am.