Quite possibly the worst experience I've had in working with a content management system is with RedDot CMS. I'm currently working with a client to update their site which is built in RedDot.
The manufacturer of RedDot claims to be "The Content Experts" but perhaps they exclude user experience from that.
I'm using RedDot, which is apparently old and has been replaced with an newer version with a new name. Hopefully they've updated everything about the user experience which is a mess of pop-up windows and cryptic ways to search for and link to images and content. One of the worst offenses, is that hitting the return key after entering text into a form to search for content for a link the page goes blank... Blank, because I hit return, and didn't click on the custom search image button which is the only way it seems to submit the form.
An unofficial blog asks the question, "Is RedDot CMS Dead?". Sadly, no. Even though it's been replaced, there are probably many customers out there of RedDot resellers who must suffer it's existence.
Being a developer and user of RadiantCMS makes me look at this from a particular perspective and will help me guide development of Radiant. With this experience, I'm officially picking a fight with other CMSes. I hope to learn a lot from other solutions and give my customers a better experience, but mostly I think its important to talk more about what is considered "enterprise" and show that the emperor has no clothes.
If you're looking for a CMS, it should be easy to understand and easy to update. If you're considering RedDot, or some vendor that provides it, think again for your own benefit.