I did a small review of editors/IDE's recently, and the most common thing missing IMO is some sort of project management, integrated debugging and ways to set up custom python paths per project.
When it comes to Komodo, as far as my quick test could ascertain, the project management in Komodo was quite basic, but it does have integrated debugging. Also the code completion drove me nuts.
Personally I use WingIDE, and I'm not missing any features at all, really. Especially I love how you can set a main file, which it will analyze and see that if the main file modified sys.path, it will analyze that path so you can do code completion and click-to-definition on those packages too. That's really nice when you use zc.buildout, for example, and a feature I looked for in other IDE's when I tested it, and didn't find many that supported it.
PyCharm, the new kid on the block, has refactoring support which looks interesting, but I don't know if it really works and how useful it is in practice.