Personally I prefer using wordpress. I find making themes for it is VERY easy, fast and very well documented. The CMS is easy enough that I can set it up and have a non technical person use it, but extensible enough that a technical person can extend it to meet just about any of their needs. Installing new (pre-made) themes, updating, installing new (approved) plugins, etc... are all done easily from within the CMS with no FTP or other knowledge required.
And even though it's designed for a blog, I've found its quite easy to use it for a more traditional site as well.