Pligg developers have released version 9.9.0 of Pligg CMS quite months ago. Now a had time to test it. In comparison to my last pligg installation of pligg 9.8.2 this version is more stable. It does not broke pages with PHP errors in the browser on every second click and you get good feeling navigating through it.
But some bugs are still there. Some links still does not work (without reporting PHP exception to the user), e.g. in Admin area or on submitting a comment to a news. Also spellchecker was broken.
Pligg templates Problem
In comparison to Wordpress, there are really few free templates for Pligg 9.9.0. Precisely I found only one and that is the default template, witch is quite ugly. There is a little bit more of templates for previous versions, but one have to mach upgrading work to get them worked just for see them in action.
I think the best way is to make your own template on base of default template. But I decided to wait till next version or even till version 1.1.0 (where I'm not sure whether it gonna be released sun :( ). Nevertheless I think it's better to take one or to version closer to 1.1.0 due possibly further changes in template handling.
Extensions of Pligg are called Modules. The handling of them is just like in Wordpress upload and enable, some of them are available with first installation. I have enabled some of them, but there were not functional except askimet. I hope this also will be better in next versions.