Introduction
After 4 hours of struggling with the abomination named Mambo documentation (I wouldn't grace it with a link) I have to conclude that it is a pure-bred torture device. Please read their documentation to get a taste of horror if you are seriously masochistic.

I am at a loss for words!

Lets begin somewhere just to give you a hint…

The documentation is sparse. The online documentation is meaningless in polite terms. It explains in detail the obvious (giving enriched meaning to the phrase "master of the obvious"), failing to explain the purpose behind it all. The context documentation isn't linked to be able to browse the rest.
Lets give one tiny example:

This page shows show a list of the Menu Items for your the munu you have just choosen.
Menu Item: This is the name of the menu item. Click the name to edit the menu item.
Section: This is the type of menu item.
Published: This is whether the item is published. See the legend below the list for an explanation of icon types.
Checked Out: This is the name of a user if this menu item is checked out. You will not be able to edit an item if it is checked out by another user. This is to prevent accidently editing an item while another User is editing it.

The documentation is full of such trivialities and it banters on and on how easy it is, how simple it is and you have to just click and you will have your website!

Proposal
Let's form a Coalition Against Open Sores projects (CAOS) whose objective would be to identify open sores projects and highlight their problems to save poor soul from drowning in their filth. Open Sores projects are Open Source projects with very poor quality product and/or documentation which are time-traps (you spend long hours after them only to realize that it is not worth it and you still haven't found a solution). And if you decide to adopt them in your projects, they bomb on your jeopardizing your project and possibly your career along with it.

Why singling out Open Source?
The noise-to-signal ratio appears to be very high for open source projects.

Looking forward for your comments and suggestions.

BTW: Please don't give me the cliche - if you don't like it don't use it, it is free.
It is free in direct cost, however it is expensive for the time to learn and support and for the cost of failure while implementing a solution based on it. And they make it a nightmare trying to evaluate products. Previously in the good old closed source era we had few decent products to choose from (and one or two bad ones which were well known). Today we have literally hundreds of open source products competing for mind-share in any give category, utterly confusing anyone trying to identify a good product.

What are your experiences with this issue? War stories welcome!