I agree with some of the comments about the lack of documentation of certain modules. Also I understand that a programmer prefers to program, and not to write good documentation for the *user*, designer, other programmers, and everything in between. I emphasise 'user' because often the documentation written is nothing more than a list of programmers geek speak, with no significance to the mortal user (or designer) of the module or software. This I find true for many more OpenSource softwares. This is, IMHO, one of the most important reasons why OS is not so wide-spread as it could be.
However, I love CMSMS for any site I can make... i.e. because I can not code *any* PHP, I will not be making too difficult sites, with custom add-ons, and exciting user specific eye-candy. I like to build very simple brochure-like sites, with good SEO. I am convinced that that is what 80% of companies want and need. CMSMS is perfect for that! I've tried the more feature packed can-do-everything CMS's (Typo3, Joomla) but before I had the site up and running, my blood pressure was 20points higher...
CMSMS is a breeze to install, fill with content, and maintain! In this case, any lack of documentation is made up for by the forums and wiki's...
